Butterfly Valley is named after a moth. The insect that made this gorge famous is the Jersey tiger, Euplagia quadripunctaria — a day-flying moth with cream-striped forewings and scarlet, black-spotted hindwings, and the only lepidopteran the European Union lists as a priority species for protection. Through July and August it gathers here in thousands, clustering on damp leaves and shaded rock along the stream, where running water keeps the air humid and walls of some 350 metres keep the wind out. More than eighty butterfly species have been recorded alongside it. The canyon cuts about four kilometres back into the seaward flank of Babadağ, the 1,975-metre mountain behind Ölüdeniz, and meets the sea at a single pebble beach with no road to it. In 1995 Turkey declared the valley a first-degree protected site, which bans permanent building of any kind.
Almost everyone arrives by boat, a crossing of about twenty minutes from Ölüdeniz. From the pebble beach a path follows the streambed inland under figs, oleander and plane trees, and the air turns cool and green as the walls close in; in half an hour it reaches two waterfalls dropping off the rock face. The water runs hardest in spring, when rain and the melt off Babadağ push it through, and thins to a thread by late summer. The other way in is the descent from Faralya, the village on the plateau above — a steep, rope-assisted scramble that catches out anyone who takes it lightly. Because nothing permanent may be built here, the camp on the beach is tents, wooden bungalows and treehouses, and it runs only from spring to autumn; in midsummer some two hundred people a day come ashore.