The full name of the world heritage site is ‘Islands and Protected Areas of the Gulf of California’, and the UNESCO site covers much of the old Sea of Cortez which Jacques Cousteau once called ‘the world’s aquarium’. Many of the mountainous islands in the gulf are home to unique species—including a rattle-less rattlesnake—and are protected from development, including the island of Espíritu Santo near La Paz. Last month I visited many of the gulf’s bays on the Baja peninsula, including Bahías de Los Ángeles, Concepción, Loreto and La Paz. In the Loreto national marine park, I saw bottlenose dolphin and fin, humpback and blue whales, including those blues in the videos below.