<Li> Antardvipa - durga (island fortress): surrounded by natural (sea or river) water bodies . E.g. Murud - Janjira . </Li> <Li> Sthala - durga (plain fortress): surrounded by artificial moats or irrigated by a river.eg Deeg Fort, Lohagarh Fort </Li> <Li> Dhanvana - or Maru - durga (Desert Fort): Surrounded by an arid area of at least 5 yojanas (73 km). </Li> <Li> Giri - durga (Hill fort) <Ul> <Li> Prantara - durga: Located on a flat hill summit . E.g. medieval forts such as Chittor, Gwalior and Ranthambore . </Li> <Li> Giri - parshva - durga: The fortifications and civilian structures extend down to the hill slope (not just the summit). </Li> <Li> Guha - durga: Located in a valley surrounded by hills, where the outposts and the signal towers are located . </Li> </Ul> </Li>

Name the important forts built by the british in india