The Romans knew it well — Tiberius turned it into a nymphaeum, and statues have been recovered from its floor — then for centuries Capri's fishermen shunned it as a mouth of spirits. Its 1826 "rediscovery" by German writer August Kopisch delivered the Blue Grotto to European Romanticism: ever since, that electric blue — sunlight entering through a submerged opening and rising filtered by the water — has been the very image of Capri.
What to see
The phenomenon is single and unrepeatable: inside the cavity the sea ignites with a blue that seems to have its own source, and anything dipped in it turns silver. The oarsmen row the circuit singing: calculated folklore, yet when a voice bounces off the vault it still works.
Visiting
Entry is only by rowing boat, four passengers at a time, lying back: the mouth is a metre high, and any swell closes the grotto without appeal. Morning gives the best light and shortest waits; the monument ticket adds to the boat fare. In summer, the bobbing queue offshore is part of the rite.
Getting there
By sea, on the island tours from Marina Grande; or by land from Anacapri, bus to the clifftop and stairs down to board the rowing boats directly. The land route is the sharper traveller's secret.
Our editors' tip
Go by land for nine o'clock, when the rowers start and the tour boats have not yet arrived: you will wait half as long. And if the sea looks doubtful, ask at the harbour before climbing to Anacapri — a closed grotto grants no refunds on effort.