Solomon Islands
A waterfall drops through pools into a cave, a day's walk out of the capital.
The trail squeezes between buttress roots, then the gorge opens: white water pouring into a deep pool, limestone walls streaming, cave mouths dark in the rock behind. The roar swallows every other sound.
The Mataniko River drops through a series of pools and into a cave system in the hills above Honiara. The guided route follows the river for about six hours there and back, and published excursions run from seven in the morning until five. Caves and crossings both depend on the water, so the guide decides on the day what is passable. Japanese soldiers held the caves behind the falls during the Guadalcanal campaign, and the gorge walls that sheltered them are the same ones the walk threads today.
Solo
A guide is the difference between a walk and a genuine river route, and going alone means moving at whatever pace the water levels allow.
Couple
A full day out of Honiara with real river terrain in it, and the cave at the end makes the whole trek worth it.
Friends
River crossings and a cave are better shared, and the guide can judge on the day whether the group swims or takes the higher route back.
Guided walks come with a boxed lunch and bottled water carried up to the falls.
Honiara Central Market, back in town, is where the fresh produce is.

Alte Rheinbrücke
Liechtenstein
A 135-metre timber tunnel over the Rhine; somewhere inside it, you change countries.

Scapa Flow
Scotland
The seabed holds a German navy, scuttled in 1919 — divers swim through drowned battleships.

Kunta Kinteh Island
Gambia
The last piece of Africa many captives ever saw, and the river is taking it back.

Naruto
Japan
Whirlpools twenty metres across spinning beneath a bridge where two seas collide.

Savo Island
Solomon Islands
Megapodes bury their eggs in black sand that an active volcano keeps warm from below.

Nendo
Solomon Islands
Money made from red feathers came from here, and the memory of it has not gone.

Kolombangara
Solomon Islands
A near-perfect volcanic cone with its rim broken open, and cloud forest all the way up.