Heritage preservation is the strategy of conserving the cultural and environmental history of a certain time and place, and it also has political, spiritual, socioeconomic, scientific, and educational significance. The resulting heritage sites exhibit the past in the present; they are preserved with the hope of shaping an ecological future. As physical and cultural heritage, architectural sites represent the accumulated myths and worldviews of the people who acted on and transformed the land over long periods of time. Examining the aesthetics and philosophy that shaped three of the most important architectural sites of the Yoruba people in southwest Nigeria unveils the various facets and values of Yoruba heritage as it pertains to conservation and environmental protection. Some of the most significant Yoruba architectural sites are located in vast, hilly areas of primary forest in southwest Nigeria. The setting, design, and cultural meaning of these heritage sites signify hope for a harmonious coexistence between society and the nonhuman world (as for exampe shown in figure 1), while also foregrounding the vulnerability of the environment.¹

The Yoruba are a large ethno-linguistic group, with more than 50 million people in the Yoruba homeland, which incorporates parts of modern-day Nigeria, Benin Republic, and Togo. They are one of the largest ethnic groups in Nigeria. Their worldviews and relationship with the environment and the physical world are informed by two realms—the heavenly celestial realm (Orun), which is invisible or metaphysical, and the earthly terrestrial realm (Aye), which is visible and physical. The disembodied heavenly beings (invisible spirits) of the metaphysical Orun are embodied in earthly elements—the physical Aye—of the nonhuman world (trees, rivers, hills, forests) at their architectural sites. The natural environment thus plays a unique role in the Yoruba cosmological worldview.²

Oduduwa Grove, or Oduduwa World Temple, (figure 2) is an urban forest in the heart of the city Ile-Ife. The site is divided into two sections that are separated by a masonry-fence wall: a constructed, semi-public section and a forested private section. The former contains residential buildings for the Oduduwa priest (the Obadio, who also doubles as the head of all other traditional priests in Ile-Ife and, by extension, Yorubaland at large), his family members, and guests, the graves of several past priests, a general courtyard, a courtyard for women (since the grounds are divided based on sex), and temples and shrines dedicated to Yoruba idols. The forested private section hosts the Oduduwa mausoleum, which is only accessible to the Obadio. One of the most significant works of architecture in the constructed section is the palace-reception building (figure 3) for the Obadio.

The palace is built of cement-plastered walls and has a zinc roof like all the other buildings in the compound, which are interspersed with trees that operate as shrines, as visible in figure 3 (left). Since the advent of Yoruba modern architecture, these industrially produced materials are used as replacement for earlier mud walls and grass-thatched roofs. Successive Oduduwa priests who have occupied the palace have conserved and renovated it according to the building technology available at the time. There are shrines in some of the other buildings, which are used—along with the Oduduwa tomb, located in the forested section of the site—for the initiation and ritual ceremonies (administered by Oduduwa priests) that precede the royal coronation of any new Ooni. Ooni is the traditional title of the King of Ile-Ife, whose palace is in another location within this core area of Ile-Ife. The Ooni is the most important traditional ruler of the Yoruba people in the homeland and across the diaspora.

The statue in figure 4 symbolizes the myths of a Yoruba creation story in which Olodumare (the Supreme God), from the heavenly celestial realm (Orun) sent Oduduwa as a messenger to create the world at Ile-Ife. According to Yoruba myth—a significant part of the Yoruba worldview that shapes its traditional religions and their associated cult systems—the human figure depicts the embodied spirit of Oduduwa, who is believed to have descended from Orun with the aid of a chain at Oramfe (another sacred landscape in Ile-Ife). A chicken, believed to have descended from Orun together with Oduduwa, is said to have spread a piece of soil—thrown from the celestial realm into the existing earthly waters—until it expanded enough to become the entire terrestrial world. For this reason, the Yoruba believe Ile-Ife, a medium-sized city-state with a human population of 409,274 (2023), is the location of the first Yoruba civilization, settled around 500 BCE, and civilization in general.³

Just as it is rich in religious and mythological history, Oduduwa Grove is also rich in urban biodiversity, constituting a unique intersection of culture, myth, heritage, and nature. Its flora and fauna offer essential ecosystem services to the microclimate of the city. The tropical rainforest at the site—and its characteristic dense foliage system—acts as carbon sink and air purifier, while also providing a cooling effect to heat islands in the city. The urban conservation site thus affords an ecological balance between the human and nonhuman worlds of the city.⁴ Being at the core of the city of Ile-Ife, the site also prevents soil erosion via the aid of the plants’ root systems.

Fifty kilometers north of Oduduwa Grove is one of the two UNESCO World Heritage Sites in Nigeria: Osun Grove. Osun Grove is a significant Yoruba architectural site located at the edge of the core of another Yoruba city, Osogbo, which was founded around 1801 by two hunters named Larooye and Oguntimehin. The site conserves a level of rainforest vegetation that documents both the tangible, architectural heritage of Yoruba city-planning—one which incorporates mystic forests or groves—and the intangible, cultural heritage of traditional religious and social principles.

Among the architectural structures of the site are the Visitors’ Reception Centre and the first and second palaces of Osogbo (figure 5), which are religious symbols of the Osun and Ogbonicult systems and contain shrines dedicated to the corresponding gods. The structures can be viewed as works of art in architectural form. Their walls are made of earthen materials and covered with high-relief murals, while their roofs are made of timber and zinc. The earthen materials may have been sourced from the Grove, as is a common practice in Yoruba traditional building construction techniques. Such materials are amenable to the production of artistic high reliefs on the walls, are environmentally sustainable, and offer indoor thermal comfort. The timber and zinc are modern building construction materials that are readily available in Osogbo. The conservation of the site was achieved before the inclusion of the Grove to the UNESCO list of World Heritage Sites in 2005, in large part due to Austrian environmental activist Susanne Wenger (1915–2009), who was herself initiated into the Obatala (the Yoruba god of creation) cult, and also became a devotee of the goddess Osun.⁵ The sculptural designs of the structures—including the anthropomorphic aesthetics of the structural carved wooden caryatids (figure 6)—and the fact they are made of environmentally sustainable materials (earth and timber) allow them to organically blend into the surrounding forest landscape. This ecological milieu is highly biodiverse, with over 400 species from 63 families—including seven species of primates (e.g., Cercopithecus species) and reptiles (e.g., Python species)—and a rich variety of vegetation.⁶

Not at least because of its rich biodiversity, Osun Grove is also a popular ecotourism site, comprising 75 hectares of primary rain forest with a 47-hectare buffer zone on the outskirts of Osogbo.⁷ This affords regular encounters between tourists and free-ranging primates, who often gather in large numbers if lured with biscuits, sweets, or bananas. Such scenes enrich the experience of visitors, especially children who are thrilled by the sight of primates peeling bananas. The annual Osun Osogbo Festival, usually celebrated every August, attracts visitors from regions of the world where Yoruba traditional religions still exist as the cross-cultural footprints of the slave trade, including Brazil, Cuba, Trinidad and Tobago, and North America.

Despite this enormous influx of tourism to the site, its environmental protection is ensured through privacy zoning, the establishment of tourist-specific walking routes, and the employment of tour guides. The preservation of the Grove is also assisted by various other actors: a full-time team of government officials from the National Commission for Museums and Monuments, which manages the site; local community members, who are largely devotees of Yoruba traditional religions; legal frameworks, which consist of laws of Osogbo Local Government, Osun State, and the Nigerian Government; and UNESCO. The local community members also cherish and welcome visitors since they act as salespeople, proud to market the Grove as their local resource and harness its economic benefits.

Osun River (figure 8) meanders through the Grove and hosts along its bank numerous shrines dedicated to various Yoruba gods, creating a harmonious combination of forested landscape, waterscape, and religious architectural structures. The river originates in Igede Ekiti in Ekiti State, part of Yorubaland, and passes through Ijesaland before reaching Osogbo. It then flows out of Osun State to Oyo State and empties into the Atlantic Ocean. Devotees of the goddess Osun believe that she resides in the river and worship her at shrines along the riverbank and on the river itself.

At Osun Grove, the natural environment blends with the animistic sculptures of the shrines that dot its open spaces and appear under some trees. The trees are not planted (not ex situ) but are rather in situ, part of the primary nature; they are believed to be inhabited by invisible spirits, gods, or demons from the celestial realm. The Yoruba taboo system signifies a belief that whoever attempts to cut the trees would be attacked by the invisible entities that dwell there, while whoever harvests fish would suffer from a swollen stomach and the fish would never get cooked. This taboo system is specific to Osun Grove, but similar versions have served as traditional environmental conservation strategies for other sacred architectural sites in Yorubaland.

About 200 kilometers southwest of Osun Grove, in the city of Abeokuta—whose Indigenous inhabitants are of Egba and Owu Yoruba origins—is Olumo Rock, a hilly cultural-architectural site 137 meters above sea level. It is an urban landscape that documents the Egba-Dahomy war between 1843 and 1851, and the Owu-Ife war between 1821 and 1828. During these two intertribal Yoruba wars, Olumo Rock (figure 10, left) offered the Egba people refuge. The Owu and Egba peoples believe that the Rock is inhabited by a protective spirit who gave them refuge from their opponents and helped them win the wars. This protective role of the Rock and its caves demonstrates how social events and ecological places are often entangled in environmental history.

By 2006, Olumo Rock’s major architectural component had been constructed: a mechanical lift (figure 10, right) to easily reach the Rock’s topmost point. The lift house consists of vertical and horizontal circulation spaces, two lift shafts covered with glass, lift halls of stone walls, top-located lift-engine rooms, and metal bridges roofed with long-span aluminum sheets on a steel-roof framework. While the stone walls of the lift halls blend with the environmental aesthetics of the rocky site and are environmentally sustainable, the glass cladding of the lift is disruptive of this organic aesthetic appeal. At its highest altitude, Olumo Rock provides views of Abeokuta city. Other architectural components constructed on the Olumo Rock site include a museum, a multipurpose hall, Lisabi garden, a restaurant, a gift shop, and a water fountain. Artificial steps were also constructed for visitors who prefer not to use the lift. The vegetation of the site, the curvilinear architectural form of the structures, and the use of granite stone walls allows it to blend in with the rocky landscape and generate a sustainable organic architecture.

The site, especially the Lisabi Garden section (figure 11), holds a rich diversity of plants that are used in the preparation of traditional medicines. These include trees like Neem (Azadirachta indica), Baobab (Adansonia malvaceae), and Flamboyant (Delonix regia). The garden is a memorial of the Egba legendary warrior, Lisabi, who led the earliest settlers in the series of wars that ended around 1830.

These three sites—Oduduwa Grove, Osun Grove, and Olumo Rock—demonstrate the power of architecture as a cultural agent with the capacity to transform and cooperate with natural spaces. The ecological locations are rife with symbolism, and bear numerous traditional identifiers of the Yoruba. They are natural milieus that are shaped by cultural practices, exemplifying how space is entangled with life and the afterlife. With the global institutionalization of cultural heritage, these sites will continue to be central to discourses on Yoruba environmental history, urban ecotourism in Nigeria, and the transportation of Yoruba Indigenous knowledge around the world.⁸

1. See, for example, Dolly Jørgensen, Recovering Lost Species in the Modern Age: Histories of Longing and Belonging (Cambridge and London: MIT Press, 2019); Cornelius Holtorf and Anders Högberg, eds., Cultural Geritage and the Future (Oxon: Routledge: 2020); Ngozi Ezenagu, “Heritage Resources as a Driver for Cultural Tourism in Nigeria,” Cogent Arts & Humanities 7, no. 1 (2020): 1734331, https://doi.org/10.1080/23311983.2020.1734331.
2. Joseph A. Fadamiro and Joseph A. Adedeji, “Cultural Landscapes of the Yoruba of South-Western Nigeria Demystified as Solidified Time in Space,” Space and Culture 19, no. 1 (2016): 15–30, https://doi.org/10.1177/1206331215595751; Joseph A. Adedeji, “Sacralising Landscapes, Constructing ‘Nature’ at Osun Grove, Osogbo, Nigeria,” in “Thinking with Urban Natures,” Global Environment 16, no. 2 (2023): 19–198, https://doi.org/10.3197/ge.2023.160202.
3. For more information on oral-history accounts of the creation of Ile-Ife, see, for example, Olakunle Michael Folami and Taiwo Akanbi Olaiya, “Gender, Storytelling and Peace Construction in a Divided Society: A Case Study of the Ife/Modakeke Conflict,” Cogent Social Sciences, no. 2 (2016): 1159015, https://doi.org/10.1080/23311886.2016.1159015; or Judith Bachmann, “Materialization through Global Comparisons: The Findings at Ile-Ife from the Late 19th Century to the 1960s,” Interdisciplinary Journal for Religion and Transformation in Contemporary Society (2023): 1–25, https://doi.org/10.30965/23642807-bja10086.
4. Fadamiro and Adedeji, “Cultural Landscapes of the Yoruba of South-Western Nigeria Demystified as Solidified Time in Space”; Adedeji, “Sacralising Landscapes, Constructing ‘Nature’ at Osun Grove, Osogbo, Nigeria.”
5. Peter Probst, “Yoruba Heritage as Project: Reauthenticating the Osun Grove in Osogbo, Nigeria,” African Arts 42, no. 4 (2009): 24–37, https://doi.org/10.1162/afar.2009.42.4.24.
6. Thierry Joffroy and O. J. Eboreime, “Nomination to the World Heritage List, Osun-Osogbo Sacred Grove,” (PhD diss., The Government of the Federal Republic of Nigeria National Commission for Museums and Monuments Abuja, 2004).
7. Godwin E. Oseghale, Emmanuel O. Omisore, and J. Taiwo, “Exploratory Survey on the Maintenance of Osun-Osogbo Sacred Grove, Nigeria,” African Journal of Hospitality, Tourism and Leisure 3, no. 2 (2014): 1–22.
8. Joseph A. Adedeji, “Urban Biocultural Identity of Yorubas: Intersection of Philosophy and Nature for Wellbeing at Osun Sacred Grove UNESCO Site, Osogbo, Nigeria,” in Urban Nature: Enriching Belonging, Wellbeing and Bioculture, eds. Charlie M. Shackleton and Michelle L. Cocks, 51–66 (London: Routledge, 2020); Joseph A. Adedeji and Joseph A. Fadamiro, “Urbanisation Forces on the Landscapes and the Changing Value-Systems of Osun Sacred Grove UNESCO Site, Osogbo, Nigeria,” Landscape Research 43, no. 6 (2018): 798–816, https://doi.org/10.1080/01426397.2018.1459525.