Many Galápagos visitors will first set foot in the islands on Baltra. This unassuming, sun-drenched, flat, rocky island has some interesting history.

Unlike most of the Galapagos Islands, Baltra is not itself a remnant of a volcano. Rather, it is what is known as an uplifted island, a patch of land that was once under water before volcanic activity on neighboring Santa Cruz Island changed the underwater geology. Because of this, Baltra is flat instead of hilly like other islands, and it is covered with rounded volcanic rocks: these are known as "pillow lava" because they look soft. They are only formed underwater.

During World War Two, the United States was concerned that Axis powers might assault the Panama Canal from the Pacific. Although Ecuador did not formally join the allies until 1945, they made a deal with the Americans to put a military base in the Galapagos, which was strategically located to protect the canal. Flat, sunny Baltra was selected as the site for the base and it was hastily built.

Activity was intense at the Baltra military base in the early years of the war. After the decisive Battle of Midway in June of 1942, the United States kept the Japanese Navy on the defensive and the threat of an attack on the Panama Canal lessened every day. By the end of the war, the Baltra military base housed only a token presence of American servicemen.

The Baltra air base was impressive in its day. In addition to the airstrip and military installations, there was a bowling alley and movie theatre (which showed the latest Hollywood movies). Prostitutes were brought in from Panama and there were bars for rowdy soldiers to blow off steam. At one time, the base employed 1,500 Ecuadorians as support staff. Tensions were occasionally high between the servicemen and the Ecuadorians, who were denied access to the movie theatre, commissary and bars. The Ecuadorians were allowed into the commissary after one Ecuadorian died and several became ill after drinking some dangerous home-brewed alcohol.

In 1945 the war ended and the Baltra air base was given to the Ecuadorian military. The Americans stripped the base of most useful items before they left, and today there is little remaining of their presence. The Ecuadorian air force maintained the base and air strip and today it is one of two main points of entry into the islands by plane, the other being an airport near Puerto Baquerizo Moreno on San Cristobal Island.

The land iguanas on Baltra have an interesting history. In 1932, scientists decided to move some Baltra iguanas to neighboring North Seymour Island to see how they would fare. They thrived, which was fortunate. During the war, Baltra iguanas became extinct, but some of the survivors from North Seymour were bred and eventually reintroduced to Baltra in 1991. Now, the most recent studies show a thriving population of more than 400 iguanas on the island, which can occasionally be seen wandering near the airport.

Despite its interesting history, Baltra does not have much to offer visitors. The airport has some gift shops inside and across the dusty street, but the military base is closed to visitors. Generally, incoming guests arrive at the airport and are whisked away to ferries and more buses which take them to Puerto Ayora on nearby Santa Cruz Island. There are no real visitor sites on the island, as there is not much to see.