Osu Castle — properly called **Christiansborg Castle** — is the historic seat of government in Accra, standing on the coast at Osu. It served as the official residence and office of Ghana's presidents from independence until 2013, when the seat of government moved to Flagstaff House (now Jubilee House). It remains a presidential property and a national monument, and it is one of the most historically layered buildings in West Africa. **Origins.** The Danes built the first fort on the site in the 1650s, naming it Fort Christiansborg after King Christian IV. It changed hands repeatedly — Danish, Portuguese, Akwamu, Dutch, and finally British — before becoming the seat of the British colonial administration in the Gold Coast. It was from Christiansborg that colonial governors governed, and it was there that Kwame Nkrumah took over the reins of government as Prime Minister in 1957 and later as President of the Republic. **As seat of government.** After independence, Christiansborg became the official presidential residence and office — the "Castle" in Ghanaian political vocabulary. Every president from Nkrumah through John Atta Mills worked from there. It was also the site of the infamous 1966 coup that toppled Nkrumah, and of the 1979 and 1981 upheavals. In 2013, under President John Dramani Mahama, the seat of government was formally relocated to the newly built Flagstaff House, which was renamed Jubilee House. The Castle was retained as a presidential asset and used for ceremonial functions and some state events. **Architecture and symbolism.** The Castle is a whitewashed coastal fortification with a central courtyard, thick walls, and a distinctive tower. It sits directly on the Gulf of Guinea, and the sound of the sea is part of its atmosphere. Beneath and around it lie dungeons that once held enslaved Africans before shipment — a sombre reminder of the transatlantic slave trade. The site is therefore both a symbol of Ghanaian sovereignty and a memorial to the suffering that preceded it. **Today.** Christiansborg is not generally open to the public as a museum, though it is sometimes accessible for official tours and state functions. It is protected as a national monument under the Ghana Museums and Monuments Board. Its future use has been discussed over the years — proposals have ranged from a presidential museum to a heritage tourism site — but its status as a presidential property has kept it largely out of routine public access. If you want, I can go deeper on any thread — the Danish period, the slave dungeons, the 1966 coup, or the move to Jubilee House.