Zanzibar: HSB students support the UNESCO World Heritage Site Stone Town

Architecture and civil engineering students at Hochschule Bremen - City University of Applied Sciences (HSB) are campaigning for the preservation of Stone Town's historic buildings. The centuries-old old town on the island of Zanzibar (Tanzania), which has been shaped by diverse cultures, is made of coral stone and has been a UNESCO World Heritage Site for 25 years. Together with their local cooperation partners, they have opened an exhibition at the Emerson's Zanzibar Foundation Gallery. This is a continuation of a project that began in May of this year, when the HSB students presented their initial findings at the Bremen Centre for Building Culture (b.zb). The current exhibition will be on display in Zanzibar until 13 November 2025.

The focus is on the CO3 project initiative: Collaboration for the Conservation of Coral Stone. It serves to understand, document and promote the built heritage of Stone Town.

Most of the historic coral stone buildings are in poor condition

Stone Town is the oldest district of Zanzibar, the capital of the Tanzanian state of the same name. The name is derived from the prestigious buildings and residences constructed mainly from the 1830s onwards using light-coloured coral limestone.

‘The district is an incredible mix of different cultures and religions, which has been strongly influenced by internal and external factors,’ says Maria Clarke, CO3 project manager and professor of building construction at HSB. ‘Factors such as climate change, tourism and urban development are forcing further change, and Stone Town is in danger of literally losing the foundations of its identity.’

Most of the approximately 1,700 historic coral stone buildings are in poor condition, and many have already collapsed. ‘The surveying and documentation of these buildings has supplemented the previously very sparse literature and documentation on Stone Town's architectural heritage, thus contributing to the improvement of data on Stone Town's cultural architectural heritage in the form of basic research,’ says the scientist.

Preserving multicultural heritage

Stone Town's multicultural heritage is not only a unique collection of buildings, but also a living testimony to cultural and religious diversity. CO3 therefore addresses not only the importance of preserving Stone Town's structures, but also the socio-cultural integrity of the neighbourhood.

‘Stone Town's culturally diverse history has had a profound influence on urban development and architectural typology. Stone Town is very different from European cities and requires a new understanding of how cities and their architectural components can develop. Our international and intercultural project can make a significant contribution to this,’ says Professor Maria Clarke.

Exhibition can be seen on Zanzibar until 13 November 2025

For the exhibition, 30 students and three staff members from Faculty 2 – Architecture, Construction and Environment at HSB, together with Ardhi University Dar es Salaam (mainland Tanzania) and the Karume Institute of Science and Technology (Zanzibar), identified, measured and documented the typical typologies of Stone Town in order to create a document for the future. Their findings are now on display until 13 November 2025 at Emerson's Zanzibar Foundation Gallery in Stone Town.