Lagoa das Sete Cidades is a lake situated in the crater of a massive volcano on the Sao Miguel Island. It’s considered as two different lakes because they are only connected by a narrow passage which is crossed by a bridge. The two lakes are Lagoa Verde and Lagoa Azul. Literally the Green Lake and the Blue Lake. They are named so because each side of the lake reflects the sunlight in different colors. The lake in the bottom of the picture supposed to be green but there were a lot of clouds so it didn’t get enough sunlight to reflect it in green. There were only a few spots where the sun shone through the clouds making the water to glow in green.
There is an other Lake next to Sete Cidades: Lagoa de Santiago. It’s a volcanic lake as well but it’s smaller than Lake Sete Cidades so the rim of the crater is more visible.