Velká Amerika (Big America, Czech Grand Canyon) is a partly flooded, abandoned limestone quarry near Mořina village, in the Central Bohemian Region of the Czech Republic (in Beroun District).
It is 800 metres long, 200 metres wide and 80 to 100 metres deep with an 18-metre deep lake on the bottom.
Mining of the limestone was conducted in the first half of the 20th century. There are other quarries nearby, one of those is Malá Amerika (Small America) about 1.3 km to the west. The quarries are connected with each other by long tunnels.
The place has several times been used by Czech filmmakers. The place is sought after by professional divers and also popular stop for tourists visiting Karlštejn Castle.