 The actual street names (running west to east) are Castlehill, Lawnmarket, High Street, Canongate and Abbey Strand.The street layout, typical of the old quarters of many northern European cities, is made especially picturesque in Edinburgh, where the castle perches on top of a rocky crag, the remnants of an extinct volcano, and the main street runs down the crest of a ridge from it.This "crag and tail" landform was created during the last ice age when receding glaciers scoured across the land pushing soft soil aside but being split by harder crags of volcanic rock.