Complex sentence: In early 1893 the Free State took the key river city of Nyangwe after a 6-week siege that decimated the city: of 1000 original buildings in the city, only one remained standing after the siege.
Split into simpler sentences: In early 1893 the Free State took the key river city of Nyangwe after a 6-week siege that devastated the city. Of 1000 original buildings in the city, only one remained standing after the siege.