Vanuatu
Jungle parts to reveal a freshwater pool so blue it looks lit from within.
The forest gives no warning. One bend off Santo's East Coast Road and the ground opens on water of impossible colour, a deep mineral blue shading to pale aquamarine at the rim, cold spring water standing under the trees as though glowing from beneath.
Nanda, known locally as Jackie's Blue Hole, sits at the head of Turtle Bay, roughly halfway between Luganville and Champagne Beach. The blue is the work of fresh spring water rising through limestone, cutting a deep pool that stays cold on the warmest days, and visitors often rank it first among Vanuatu's blue holes, on an island with serious rivals. The keepers have made it easy to stay awhile: a covered area, picnic tables, a small bar and a swing with its own platform ring the water. Be honest about scale when planning: this is a compact pool rather than a day-filling landscape, which is why operators fold it into a single day with Riri, Matevulu and Port Olry's beach. Pay the local fee, use the marked entries, and let the depth reveal itself before anyone jumps.
Couple
Come early ahead of the tour circuit, float in the cold blue with the forest overhead, and move on north when the first minibus arrives.
Family
The picnic area and swing platform make it an easy stop with children, with the deep centre respected and the shallows theirs.
Friends
Fold Nanda into a blue-holes day with Riri and Matevulu, and let the swing settle who buys the drinks at the bar.
The small bar at the water's edge keeps cold beer and soft drinks for the gap between swims.
Make Nanda the morning stop, then drive north for coconut crab at Port Olry's beach shacks while your hair is still wet.

Velas
India
Tiny turtle hatchlings scrambling for the Arabian Sea while a whole village stands guard.

Zakynthos
Greece
A smuggler's ship rusts inside a cliff-ringed cove while loggerhead turtles nest on the southern sand.

Agua Azul
Mexico
A staircase of turquoise cascades tumbles through jungle, each pool bluer than the last.

Comporta
Portugal
Rice paddies end where the dunes begin, an undeveloped Atlantic beach running for hours.

Port Vila
Vanuatu
A capital where France and Britain ruled at once, and kava quiets the harbour at dusk.

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

Vao Island
Vanuatu
Giant tam-tams boom across a ten-minute strait; on Vao, rank is earned, never inherited.

Gaua
Vanuatu
A lake curls around an active volcano, then leaves the island as Vanuatu's highest waterfall.