The green lagoon is located in the Copiapo mountain range, 260 km from the city towards the mountain range. It is located over 4,300 meters above sea level and the landscape is incredible. You must go by 4x4 car and my recommendation is to go with local guides, I went with @geoturismolickanantay since it is a quite hostile route, without internet connection and the weather conditions can be extreme, you have to know the place.
On the side of the lagoon there are 2 thermal pools and a mountain refuge, since this route is part of the route of the 6 miles. For all the volcanoes above 6 thousand meters above sea level that are in the area.