The entrance to the Firth of Forth, an estuary in southeast Scotland, is guarded by a number of islands, the two largest and most popular for diving being the Isle of May or May Isle, 7km (4.5 miles) from Crail in Fife and the Bass Rock, or The Bass, located 2km (1.2 miles) offshore and 5km (3.1 miles) northeast of North Berwick in East Lothian. Both rocky islands are usually visited on a day dive trip in which divers can enjoy three dives amidst some of the most spectacular coastal scenery in the British Isles. The other principal islands are Inchkeith, Inchmickery, Inchgarvie, Inchcolm, Alloa Inch and Tullibody Inch.