Welcome to Earth sounds like a greeting to aliens—which most of us might as well be, considering how little we know about our planet.

Actor Will Smith sets out to explore its far reaches in Welcome to Earth, a Disney+ original series from National Geographic. Three years ago, Smith led another National Geographic series about Earth’s wonders, One Strange Rock. This time the host leaves the studio to venture into some of the planet’s most extreme environments—deep seas, deserts, glaciers—with a diverse group of researchers and adventurers.

Over six episodes, Smith proves game for anything, even if initially wary. “My grandmother used to say all the best things in life lived on the other