Palau's appeal is built almost entirely on what's underwater — and a few remarkable things that float on the surface. This is one of the world's great diving destinations, and the marine life here is extraordinary by any standard.
The Rock Islands Southern Lagoon is the centrepiece. About 200 uninhabited limestone mushroom-shaped islands rising from a protected lagoon, surrounded by reefs that hold some of the densest concentrations of marine life on the planet. The whole area is a UNESCO World Heritage Site. Day trips from Koror take you through passages, past blue holes, and along walls dropping hundreds of metres.
Jellyfish Lake is one of those experiences that's hard to exaggerate. A landlocked marine lake on Eil Malk island holds millions of golden jellyfish that have evolved without stingers — you can snorkel among them as they pulse through the water. It's surreal and peaceful in equal measure. Note that scuba diving is banned here, and the permit (currently $100) is separate from the Rock Islands fee.
Diving is world-class at sites like Blue Corner, Blue Hole, German Channel, and Chandelier Cave. Sharks — grey reef, whitetip, hammerhead — are common. Manta rays frequent German Channel year-round. The WWII wrecks in the lagoon, including Japanese ships and aircraft from the 1944 Operation Desecrate, are a bonus for wreck divers.
Peleliu is for history. The island was the site of one of the bloodiest battles of the Pacific War, and the coral ridges, jungle, and rusting equipment left behind make for a sobering visit. The small museum gives context, but the real impact comes from walking the terrain.
Babeldoab, Palau's largest island, is the opposite of a beach resort. Jungle-covered hills, waterfalls, traditional villages, and the ancient stone face carvings at Badrulchau make it worth a day trip or two. The road around the island was paved with Japanese assistance in the 2000s and is now navigable by car.