From lava tubes on Mars to ice pockets on Europa, subterranean environments may offer the best chance of finding life—and living safely—beyond our planet. “I was like, ‘OK, I'm pretty sure that ...

Could ancient humans really have built the pyramids without extraterrestrial help? Or do such questions reveal more about modern anxieties than the past itself? The idea that aliens assisted the ...

Erich von Däniken proposed that monumental structures such as the pyramids could have been built with help from aliens. Stefan Baumann Could ancient humans really have built the pyramids without ...