Get ready for some serious tube-geekery, because there's a new app called Disused Tube that tells you where all the ghost tube stations are in London. The app has a guide to over 50 abandoned underground stations, with detailed history, photographs and audio commentary. As well as a map showing all the disused stations, it's also got two walking tour maps so that tube fanatics can go on a self-guided tour of some of the stations.
If you still can't get enough, there's some bonus information on six railways that used to be part of the tube network – who knew you used to be able to get the tube to Southend? The app has been co-created by Geoff Marshall, who's held the Guinness World Record for travelling to all tube stations in the fastest time possible, not once, but twice, so he knows his stuff. And it's all available offline, so you won't get caught down a tunnel without all your nerdy tube facts at the ready.
Disused Tube is £2.99 and currently available for iPhone and iPad. Find out more here.