4-Day Northern & Western: Sullivan Bay's Fresh Lava

Most Galapagos itineraries begin here. Baltra's airport is the world's first fully ecological airport, run on solar and wind power and built largely from recycled materials, including old oil pipes repurposed into the terminal structure. Land iguanas, wiped out here by the 1950s and reintroduced through a decades-long breeding program, now number in the hundreds again, some right around the airport grounds. From the terminal, a short bus transfer brings you to the pier for the panga ride out to your ship.

A relaxed, sandy stop on Santa Cruz's north shore. A lagoon just behind the beach occasionally draws flamingos and other shorebirds, and the beach itself is one of the archipelago's main sea turtle nesting grounds, most active between December and June. It's an easy visit, as much about the swim as the wildlife.

A stone stairway carved into the cliff climbs to a wide plateau holding one of Genovesa's largest seabird colonies. The trail passes through a small Scalesia forest, home to the short-eared owl, one of the few predators on the island, before reaching cliffside colonies where Nazca and red-footed boobies nest side by side, frigatebirds wheel overhead, and thousands of storm petrels dart in and out of cracks in the lava. A small colony of fur seals sometimes gathers near the landing. Red-footed boobies nest in only a handful of places across the archipelago, and this is one of them.

A wooden staircase of 372 steps climbs Bartolome's extinct volcano from a lava-and-concrete dock or sandy beach, depending on conditions. Along the way, red, orange, black, and even green volcanic layers mark the slopes, home to pioneer plants like the island-endemic Tiquilia nesiotica, lava cactus, and scattered Scalesia. With some luck, a lava lizard crosses the trail. At the top, the view over the twin bays and the iconic Pinnacle Rock is the reward for the climb. Back at sea level, a snorkel around the coral reef and submerged lava rocks is a good bet for Galapagos penguins and white-tipped reef sharks, with sea turtles and manta rays turning up now and then too.

Despite the name, Los Gemelos aren't volcanic craters. They're twin sinkholes, formed when empty underground magma chambers collapsed, set in the misty highlands of Santa Cruz and ringed by dense, endemic Scalesia forest. A trail loops around both rims through some of the lushest vegetation in the islands, one of the better places in the archipelago to spot a short-eared owl hunting in daylight, and, with patience, the increasingly rare vermilion flycatcher.