Ogasawara Islands

Tokyo, administratively. A thousand kilometres south of it in reality, and there is no airport, so the only way in is the Ogasawara Maru, which takes 24 hours from Takeshiba pier and sails roughly once every six days. That schedule sets your trip length before you decide anything else: you will be on Chichijima for five or six days, because the ship is the only way home.

The islands have never been connected to a continent. Everything that lives here arrived by wind, water or wing and then evolved on its own, which produced hundreds of endemic species, most famously the land snails that are to these islands what finches were to the Galapagos. UNESCO listed them in 2011 for exactly that reason.

In the water: spinner dolphins that boats take you out to swim alongside, sperm whales resident year round, and humpbacks passing between February and April. The reefs are healthy and the visibility is unlike anything within reach of the mainland.

The human history is odd. The first permanent settlers, in 1830, were a mixed group of Westerners and Hawaiians, and their descendants still live here with names like Savory and Webb. The islands were under American administration from 1945 until 1968, so islanders in their seventies went to school in English.

Iwo Jima belongs to the same chain and cannot be visited.

Book the ferry months ahead for summer. Accommodation is small-scale, cash is useful, and when the ship leaves it does not come back for the better part of a week.