The Burren, or Boireann meaning a rocky place, is 100 square miles of limestone rock in Co. Clare. The Burren is a wilderness, flat and sloping and broken by great hillsides of limestone separated by cliffs like giant steps. The area is rich in archaeological sites. There are 68 megalithic tombs, over four hundred ring forts and the remains of more than 800 houses or huts. It is also a botanists paradise. Growing side by side are arctic and alpine plants, temperate climate flowers and species from the Mediterranean. This enigma has intrigued botanists for years and is a favourite haunt of theirs. The Burren comprises mainly of limestone formed over the centuries from the sediments on the seabed being compressed into stone. The stone fissures were created by rainwater which permeated the rock. There are many underground rivers and lakes, caverns and chambers, one which is open to the public is called Aillwee cave.