Photographers risk arrest to capture urban decay
4 December 2013 Last updated at 21:15 GMT
When most people take photographs of their travels, they are not usually images of buildings, abandoned, unloved, and decaying.
However, two young photographers, who call themselves urban explorers, are fascinated by what many people pass by.
Daniel Marbaix and Danny Barter have published a book, States of Decay, based on their travels in the US.
They have also roamed the UK and Europe, often getting arrested for trespass as they go.
They talked the BBC's Philippa Thomas through some of their photos.