Complex sentence: Staffa's most famous feature is Fingal's Cave, a large sea cave located near the southern tip of the island some 20 m high and 75 m long formed in cliffs of hexagonal basalt columns.
Split into simpler sentences: Staffa's most famous feature is Fingal's Cave. This is a huge sea cave near the southern tip of the island some 20 m high and 75 m long formed in cliffs of hexagonal basalt columns.