Due to its centrality, Santa Cruz is the most commercial island of the Galapagos archipelago. It is one of only four inhabited islands and its town Puerto Ayora is the most populous one in Galapagos. Most Galapagos accommodation facilities are located in Puerto Ayora and most tours start from the airport of Baltra that lies to the north of Santa Cruz. Santa Cruz Island has numerous visitor sites. The most visited ones by cruises are the tortoises breeding center at the Charles Darwin Station and the Highlands of Santa Cruz.