Cardiff is situated near the Glamorgan Heritage Coast, stretching westward from Penarth and Barry – commuter towns of Cardiff – with striped yellow-blue Jurassic limestone cliffs. The Glamorgan coast is the only part of the Celtic Sea that has exposed Jurassic (blue lias) geology. This stretch of coast, which has reefs, sandbanks and serrated cliffs, was a ship graveyard; many ships sailing to Cardiff during the industrial era were wrecked around this hostile coastline during west/south-westerly gales. Smuggling, deliberate shipwrecking and attacks on ships were also common.