I have to admit, I'm a bit obsessed with Central Asia, especially in the nineteenth and early twentieth centuries, ever since I was working on research for a novel. Travel writing from that time provide a fascinating window into a way of life now forgotten, and makes for great adventure reading (when you can find it). See Sven Hedin, Peter Fleming, Owen Lattimore and others. Maybe I'll post a more extensive list later.
In pictures: Russian Empire in colour photos (BBC)