Sete Cidades

Sete Cidades is the Azores' signature image: a vast volcanic caldera on western Sao Miguel, its floor holding twin lakes that read as two colours - Lagoa Azul mirroring the sky in blue, Lagoa Verde tinting green with depth and algae - divided only by a narrow bridge. Legend does the explaining, telling of a green-eyed princess and a blue-eyed shepherd whose forbidden parting filled the crater with their tears; geology answers with a caldera roughly five kilometres across, rimmed by walls that carry some of the island's best walking. The Vista do Rei viewpoint delivers the postcard from the southern rim, the Mata do Canario trail walks the crest past Lagoa do Canario and the famous aqueduct arches, and down inside the crater a small village lives its quiet farming life between the two shores.

What you actually see

• The twin colours - blue and green lakes split by one bridge.
• Vista do Rei - the classic full-caldera panorama from the rim.
• The rim trail - crest walking from Lagoa do Canario round the walls.
• The crater village - farms and a church on the caldera floor.

When to go

May to September offers the best odds of clear rims, with July's hydrangea hedges lining the roads in blue. Mornings beat the afternoon cloud build-up more often than not.

Honest expectations

Fog is the honest risk - the caldera can vanish entirely, so keep the visit flexible and pounce on clear windows. The two-colour effect depends on light and angle; from the water's edge they are simply two handsome lakes. Rim roads are narrow with soft shoulders.

Nearby

Ponta da Ferraria's ocean hot spring, Mosteiros' black beach and Ponta Delgada.