It happens all the time. You’re on a cruise. You’re enjoying the gorgeous weather from the top deck. While you’re surrounded by seemingly endless turquoise water. Suddenly, your view is interrupted. There are islands up ahead. You have no idea what they are or where you are. But the ship keeps moving. You snap a few pictures, dream about what’s on the islands, and ultimately forget them once you reach your final destination.

Not this time. On this trip, you’re going to pay attention, do your homework, and actually learn about the islands around you. It’s an island cruise after all. Silversea’s Silver Explorer will sail through Melanesia. The cruise begins in Lautoka, Fiji and ends in Cairns, Australia. It’ll stop in Vanuatu, the Solomon Islands, and Papua New Guinea along the way. It’ll also pass some islands about which you’ve never heard.

The D’Entrecasteaux Islands are on the latter list. The archipelago sounds French. That’s because a French navigator was the first European to see it in 1792. But the three islands—plus a handful of islets—look Melanesian. They’re volcanic, covered with mountains and jungles, ringed with fertile coasts, and surrounded by pristine reefs.

Goodenough, Fergusson, and Normanby Islands (from northwest to southeast) sit in the Solomon Sea near the eastern tip of New Guinea. After the French named the islands, the British made landfall in 1874. Australian missionaries, who dug gold mines and built copra plantations, arrived after that. But it’s World War II that created long-lasting changes on the three islands. Japanese troops were trapped on Goodenough, the Royal Australian Air Force built Vivigani Airfield on the same island, and the United States Navy established a boat base on Fergusson. After the war, the airstrip was used for commercial flights until 2006.

Boats are now the only ways to reach the islands. Dinghies regularly depart East Cape, Papua New Guinea for Sewa Bay on Normanby Island. Your ship sails pasted Normanby in favor of Fergusson, though. The largest of the D’Entrecasteaux Islands is famous for two things: birds and hot springs. The Dei Dei Hot Springs lie near the island’s south coast. They’re surrounded by pools of mud and warm streams. People who live here use the boiling water to cook food in palm fronds and pandanus-leaf baskets. While brightly colored eclectus parrots and olive-backed sunbirds fly between trees that line the geysers. It’s amazing what you’ll discover on off-the-beaten-track islands.