60 Meters Deep, Nearly Lifeless

Hundreds of geometric earthworks - squares, circles and connected ditches - hidden under Amazon rainforest until satellite imaging revealed them. Pre-Columbian civilizations built these massive structures. Their purpose remains completely unknown.

This frog is essentially a mouth with legs. It buries itself with only its eyes and horned ridges showing, looking like dead leaves. It can eat prey up to half its own body weight, including other frogs, small mammals, and snakes.

A witnessed meteorite fall in 1907 produced fragments containing presolar grains older than the Solar System. Material that formed around dying stars, preserved inside a rock that fell on Brazilian farmland.

Crystal-clear lakes formed in collapsed limestone caverns. Visibility exceeds 70 meters. The clarity comes from limestone filtering and calcite precipitation. Underground rivers connect lakes that appear isolated.

Once thought to be a protozoan, this pneumonia-causing organism is actually a highly derived fungus that evolved to be an obligate parasite of mammalian lungs, losing the ability to grow outside the host.

Skulls of the extinct Botocudo people show unexpected genetic affinities to Pacific Islanders. How did this happen before Columbus? Did ancient travelers cross the Pacific? The mystery reshuffles American prehistory.