Vanuatu
Walk off a beach into a 200-metre sunken liner, hit by her own navy's mines.
You wade in from the shore, swim fifty metres, and the seabed falls away onto the hull of an ocean liner lying on her side in blue water. Corridors run into darkness below you. Somewhere inside, a porcelain lady and her unicorn still preside over the first-class smoking room.
Launched in 1931, the President Coolidge carried a gymnasium, a theatre, a ballroom and two swimming pools before the war stripped her into a troop transport. On 26 October 1942, entering Santo's Segond Channel with more than 5,000 troops aboard, she struck two of her own navy's mines; her captain drove her at the shore, and in the hour before she slid under, all but two men walked, climbed or swam to safety. Those two dead make her a war loss as well as a dive, and she is treated with that respect. The 200-metre wreck now lies between 21 and 70 metres on a slope beginning a short swim off the beach, inside the marine reserve declared over these waters in 1983. Ten to fifteen dives barely cover her holds, promenades and cargo; the deepest rooms belong to technical divers, and every route is planned to certification and conditions.
Solo
Join a local operator and let your certification and recent experience set the route; the upper decks alone repay a week of diving.
Couple
Book a series of progressively deeper dives and end each afternoon comparing which corridor, artefact or shaft of light stayed with you.
Friends
Split across skill levels, beginners on the exterior and trained divers deeper, and agree before descending that nobody follows the group past their limit.
Bombua Beach House, two kilometres from the wreck, plates lobster from local waters and poulet fish for the surface interval.
In Luganville, Lapita Lodge prepares traditional bunia or laplap for groups who ask ahead, the island's earth-oven cooking after a day inside a liner.

Manuel Antonio
Costa Rica
Capuchins patrol the sand beneath dozing sloths where rainforest walks into the ocean.

Vaitupu
Tuvalu
Tuvalu's largest island, where traditional sport te ano sends two woven balls flying at once.

Tortuguero
Costa Rica
Jungle canals where green sea turtles haul onto black volcanic sand under a moonless sky.

Kadavu
Fiji
Manta rays circle the world's fourth-largest barrier reef, off villages the road barely reaches.

Mount Yasur
Vanuatu
Molten rock bursts skyward several times an hour from a rim you reach at dusk.

Pentecost Island
Vanuatu
Men dive headfirst from 30-metre towers, forest vines cut so they just touch the earth.

Champagne Beach
Vanuatu
At low tide the shallows fizz: volcanic gas rising off the seabed named this beach Champagne.

Malekula
Vanuatu
Jungle ridges crossed village to village on foot, Ambrym's volcano glowing across the water at night.