The valley of the city of Cusco was once an immense lake that covered a great distance and had a great variety of marine fauna such as fish and mollusks. On the shores of this lake lived mammals of megafauna and at the same time the first men appeared who were engaged in hunting, fishing and gathering fruits.
The length of this lake would have been the distance of the current districts of Cusco, Wanchaq, Santiago, San Sebastián and San Jerónimo. In volume two of the University Magazine of San Antonio Abad University of Cusco it talks about the scientific expedition of the Yale University of Hiram Bingham in 1911 and then the arrival of the geologist Herbert Gregory in the same expedition.
Gregory gave the lake the name Morkill in honor of the Southern Rail chief who helped transport the tools and belongings for this investigation. Not only Gregory but other professionals made discoveries of the fauna that lived on the shores of this lake.
Remains of this ancient lake can be seen in the Regional Historical Museum of Cusco Casa del Inka Garcilaso de la Vega. In several rooms, starting from pre-history, you can see remains of a Mastodon (relative of the mammoth), remains of algae and shells, and, finally, the intact remains of a Gliptodonte (relative of the armadillo).
Continuing with the story, as years passed with the clash of tectonic plates, the lake drained to the south in what today is known as Angostura, located in the San Jeronimo district. Through it draining out all the water and left this great valley of Cusco fin which we live.
The Huasao wetlands and the Huacarpay lake are an example of what this great lake would have been. After this event, the first human cultures such as Marcavalle and Chanapata began the great population of the Cusco Valley.
Before then the valley of Cusco was really a lake that would have housed animals of mega fauna belonging to the Pleistocene of the Quaternary era.