Did you know there was once an asylum in Caterham? It housed over 1,500 at a time. You can explore this, and some of Caterham's other historic buildings and churches, by walking this town trail from The Bourne Society, with the leaflet available here and the map here.
If that's got you curious, there's an extended piece on the asylum here
Getting there: jump on the 407 bus to Caterham, or take the train from Whyteleafe.