Meet the loo lady of London
21 May 2014 Last updated at 15:28 BST
A London guide called Rachel Erikson is offering a tour with a difference.
Rather than show off some of London's most famous or glamorous sights, she offers tours of London's toilets and their history.
Her business is called Loo Tours and it attracts visitors from all over the world. But she says British visitors seem the most enthusiastic on the subject.
Rachel took BBC News along for a look at some of her favourite London lavatories.