There are water tanks in cities all over the U.S., most of which are drab and vacuous. Not so in Germantown, Maryland. There, a 100-foot tank holding two million gallons of water is beautifully painted to resemble the Earth as seen from space, with green continents, blue oceans, and wispy white clouds on the tank’s spherical surface.

In 1980, the students of Montgomery College’s Germantown campus were tasked with designing the water tank that stood on the edge of their university. After a vote, the students designed that the spherical tank would emulate the Blue Marble. It was dubbed “Earthoid.”

The school commissioned artist Peter Freudenberg, who had worked on similar spherical projects in the past, to paint the scale model globe. He used a National Geographic globe image and satellite photos from National Oceanic and Atmospheric Administration for reference.

Two months later, the gigantic Mother Earth mural was complete. The Earthoid has gotten a new paint job since then, but still stands today and acts as a powerful symbol for environmental protection every year on Earth Day.