The Castelo do Bode reservoir developed in 1951, with the construction of the dam with the same name, located in the terminal section of the Zêzere river.

Occupying an area of around 3300 hectares, it has a maximum length of 60 km and has a total storage capacity of around 1100 hm³. Currently, it is the largest national water reservoir, serving more than two million inhabitants in the Greater Lisbon area. In the surroundings of this reservoir there are several riverside villages, namely Várzea de Pedro Mouro, Foz da Sertã and Trízio (municipality of Sertã). This reservoir is a truly paradisiacal place, with numerous river beaches, a wakeboard resort (the first in the world) and the well-known Lago Azul.

The Castelo de Bode Nautical Station (ENCB) is a dynamic center for activities linked to the Castelo de Bode Reservoir for the development of an entire network that integrates the three basic elements of the region: the reservoir, the landscape and the culture.

The origin of the name Castelo de Bode is shrouded in mystery. The most common version tells us that when some engineers were carrying out the study for the construction of the dam, they came across a stone that had the design of a castle and the head of a goat. The new toponym was then established. But there are those who prefer to associate the name with the Templars and a deity that they themselves would worship.