Caldera de Bandama is a broad volcanic crater southeast of Las Palmas, about a kilometre across and roughly 200 metres deep. The rim viewpoint is the easiest way to take in the scale of the crater and the surrounding north-coast landscape.
There are walking routes around and into the caldera, with terraced fields and palms on the crater floor. It is a good short nature trip from the city, especially if you have a car.