Pateira de Fermentelos

Where is Pateira de Fermentelos?

Countries on its shores: Portugal.

Largest lake of: Portugal.

Middle of the lake: 40.55° N, 8.50° W

The story behind it

This lake has no fixed size: its surface and depth change with the seasons, and at its largest it covers a little more than 5 km². Its water comes from the River Cértima, from a stream called the Ribeira do Pano and from water under the ground. Around the open water lie reed beds and marshes, a perfect home for birds. Purple herons and little bitterns live in the reeds, while marsh harriers and black kites fly overhead. Kingfishers and ducks can be seen too, and pike, carp and perch swim below. Red swamp crayfish live here in large numbers, but they are an invasive species that does not belong here. Since 2012 the lake and the valleys around it have been protected as a wetland of international importance. Pateira de Fermentelos is Portugal's largest natural lake – a little bigger than the famous Lagoa das Sete Cidades in the Azores, which covers about 4.35 km².

Find it on the globe

Pateira de Fermentelos is there as a small blue dot with its name, right on the water. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.

It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.