In 1896, the British-supported Sultan of Zanzibar suddenly died, poisoned by his cousin Khalid bin Barghash, who immediately assumed power. Unfortunately for the new Sultan, the British Empire preferred a different Sultan. This disagreement would lead to a war that took less time to prosecute than the one against Saddam Hussein.
With considerably fewer casualties.
In the late 19th century the "Scramble for Africa" was in full swing. European nations were invading, colonizing, and dividing up Africa. Most of the continent would be consumed by resource-hungry imperialist powers. By the end of 1914 and the beginning of the First World War, only Liberia and Ethiopia were left as independent states.
The one time you would never want to be Belgian.
So it was a big deal when the new Zanzibari Sultan was deemed unacceptable to the British, who preferred an Omani, Hamoud bin Mohammed. Since Barghash still had to get the permission of the British Consul in Zanzibar before he could ascend the throne (a condition of a peace treaty signed ten years prior; no one negotiates a treaty like the British Empire), the British demanded he leave the palace and drop his claim to the throne. Instead, Barghash barricaded himself inside.
Ugh, Zanzibar. Who would want that godawful place?
When the ultimatum ran out, the Royal Navy began to bombard the palace with high explosive shells. There were skirmishes in the harbor and the approaches to the palace, and as the Zansibari flag was shot off its pole in front of the palace, the deposed Sultan fled.
The attackers installed Mohammed as sultan, effectively ending Zanzibar's independence. Five hundred Zanzibaris were either killed or wounded with one British sailor injured. The entire incident took 45 minutes, the shortest war in history.
The damage from the Anglo-Zanzibari War
Barghash sought refuge in the German Embassy. He later fled to German East Africa (now Tanzania) before being captured by the British during the East Africa campaign of World War I. They exiled him to St. Helena and the Seychelles.