WATCH: Drone captures AMAZING 'inner-Earth' footage
Incredible drone footage has captured this amazing lake in Portugal - with a surprise secret
Covão dos Conchos - The Secret in Serra da Estrela, Portugal
At first, you may think this is just footage panning over a beautiful lake.
But soon you realise the incredible waters in Serra de Estrela in Portugal hide a bizarre secret.
Filmed by a drone, you can see a huge hole in the river, with water pouring down beneath.
The hole seems like a vortex, consuming the waters around it.
But this isn’t a gateway to the inside of the Earth.
It’s a dam, responsible for the water diversion between Ribeira das Naves to Bayou Lagoon Long.
The tunnel, built in 1955, has more than 1500 meters and creates the illusion that the dam is broken.
The video has gained a lot of attention since being posted to viral site Imgur this week.