Three things you won't want to miss in London this weekend

1. Somerset House is putting on a wonderful series of free, drop-in events to mark Earth Day, the world’s largest environmental event which falls on Sunday. Don't miss Michael Pinsky’s ‘Pollution Pods’ letting you immerse yourself in different atmospheres in cities around the world. There'll also be drop-in talks and events throughout the day from some of the artists and contributors. 

2. Make for The Dark Arts Fayre on Sunday, a macabre market where you’ll find taxidermy, books, comics, art and clothing from Satanic Flea Market regulars. You'll find the witchy gathering at Holloway's Kolis from 12noon. Entry is £3. 

3. Grab a rare chance to explore London Transport Museum’s fascinating working store containing some 370,000 items The Museum Depot Open Weekend. Look out for vintage station signs, tube maps, train carriages, taxis and the crumpled remains of an ill-fated spiral escalator. Head along to their depot in South Acton from 11am. Entry is £12.