Most of Northern Ireland's major attractions lie at its fringes. To the north are the green Glens of Antrim and a coastline as scenic as anywhere in Ireland, with, as its centrepiece, the bizarre black basalt geometry of the Giant's Causeway. In the southeast, County Down offers the contrasting beauties of the serene Strangford Lough and the brooding mass of the Mourne Mountains. To the west, the inland counties of Tyrone and Fermanagh are dotted with megalithic remains and ruined Plantation castles; while Tyrone's main attraction is the wild and desolate Sperrin mountain range, Fermanagh has Lough Erne, a fabulous place for water sports, fishing and exploring island monastic remains. However, to get to grips with the history of the North, a visit to its cities is essential: Belfast, with its grand public buildings, was built on the profits of Victorian industry; Derry has shed the security barriers and barbed wire that formerly shrouded its medieval walled town; and the cathedral town of Armagh, set on seven hills, is where St Patrick established Christianity in Ireland.