What's more, there's an extensive underground system of over 350 caves, which makes exploring below the earth's surface just as fun and interesting as exploring above it. (galavante.com)
The London Underground Mosquito (Culex pipiens molestus) has been found in underground systems around the world. (sciencedaily.com)
The man in charge of London's bus and underground system for the last five years is to step down, it has been announced. (politics.co.uk)