"Bet il Sahel" means shore house. The Bet il Sahel Palace (on the left) was originally a rectangular building. In the 1870's sultan Barghash added a pavilion (visible behind the boat-tank) The boat-tank was intended to make extra water available for the people and animals in the palace. Note the old cannons on the right.
Emily Ruete wrote about the Bet il Sahel palace: "There is a splendid view of the sea.... The doors on the upper floor, which contained many rooms, open upon a long and wide gallery of such grandness as I have never seen equalled. The ceiling is supported by pillars and these pillars are connected by a high parapet, along which chairs are placed. A great many coloured lamps, suspended from the ceiling, throw a magic glow over the whole house after dark. The gallery looks down upon a courtyard, always full of bustle and noise. ... Two large separate flights of stairs lead from this court to the rooms on the first floor. Crowds of people are continually going up and down these stairs, and the crowding is often so great that it takes some minutes before one can get to the staircase at all"
The Sahel palace and the clock tower were destroyed in the 1896 by the British (Shortest war ever) The new clock tower was incorporated in the rebuilt "House of Wonders" The House of Wonders was originally built in 1883 and rebuilt after 1886.
The Bet Il Sahel palace was connected with a bridge / passage to the Bet il Tani palace. below the bridge was the Turkish bath house. It was in Bet il Tani where Sultan Seyid bin Sultan (Emily's father) lived with his wife a Persian princess Sheshadeh, who he later divorced. Sheshadeh had a wild love affair with one of her Persian guards.
Below an old film of Zanzibar: