From Wikipedia: http://en.wikipedia.org/wiki/House_of_Wonders
The House of Wonders or Palace of Wonders (in Arabic: Beit-al-Ajaib) is a landmark building in Stone Town, Zanzibar. It is the largest and tallest building of Stone Town and occupies a prominent place facing the Forodhani Gardens on the old town's seafront, in Mizingani Road. It is located between the Old Fort and the Palace Museum (and former Sultan's Palace). It is one of six palaces built by Barghash bin Said, second Sultan of Zanzibar, and it is said to be located on the site of the 17th-century palace of Zanzibari queen Fatuma. The House of Wonders currently houses the Museum of History & Culture of Zanzibar & the Swahili Coast.