Portland, at Dorset's southerly point, is almost an island, being joined to the mainland only by the causeway Chesil Beach. The best way to explore this area is by foot. There's a good network of footpaths which allow access to several sites of special scientific interest. The chalk and limestone grasslands are a haven for butterflies and several rare species can be spotted here. Around the coves and rocks you can take in the atmosphere as the waves crash against the shore. You'll see several shipwrecks and interesting geological features carved out by the power of the water.