Inside the Sete Cidadescrater there are two lagoas: Lagoa Azul - the largest - and Lagoa Verde.
Along the Lagoa Azul you'll find the village of Sete Cidades
Because these lakes are situated inside a crater all the water in the area floods into the lake, which caused so frequent flooding of the village, that in the 1930's it was decided to dig a tunnel to relieve the village from excess water.
The tunnel is directed west towards Mosteiros on the westcoast.
The tunnel has a length of 1200 m. and the water is chanelled through it by means of a levada which leaves sufficient walkingspace- also in height!
Luckyly the constructors added a small sign on the wall every 10 meters indicating the distance, which made it possible to hide a cache inside the tunnel!
The path has some wet places of ( at our time in the end of August) 1-2 cm. water => no rubber boots or so necessary.
The cache is hidden 595 m. from the Sete Cidades entrance and thus 605 m. from the Mosteiros entrance !