The Daniel-Johnson hydroelectricity dam, formerly known as Manic-5, on Lake Manicouagan, Quebec.
Its highest point is 702ft tall, about 1.5x the height of the Great Pyramid at Giza, it’s 4,311ft long and was built with 2,900,000 cubic feet of concrete, making it the largest dam of its kind in the world. Power from the dam supplies not only Quebecers’ needs, but is sold to neighboring US states.
The Manicouagan reservoir is an annular lake formed from a meteor impact crater with a 45-mile diameter; it’s the 6th largest meteor crater in the world. The central island’s tallest peak is called Mount Babel.
The ring shape seen today is the result of geoengineering to re-flood valleys and connect formerly separate arcs of the crater lake; the last image above shows the lake boundaries in 1962.