Without sunlight: Years.

A popular stunt for daredevils is to be buried alive. In 2004, Czech magician Zdenek Zahradka set the world record after spending 10 days in a coffin underground, where he had a tube for breathing but no sunlight, food, or water.

But the world record for living the longest without sunlight might actually go to a child. In 2012, Russian police uncovered a cult living underground in the Republic of Tatarstan, where many of the children cult members had reportedly never seen the sun.

Why you shouldn't try this: Sunlight is an important source of vitamin D, which helps the body absorb calcium for bone health. It also triggers the release of serotonin, which regulates sleep, mood, and appetite.