Season 3

Spot a giant glacier on the red planet, let the milky seas off the coast of Java bathe your vision, ponder a huge hexagon floating above Saturn, and take a spin around a doughnut-shaped lake in Saskatchewan.

Explore strongholds abandoned by their architects. Look at a lost city in the Amazon jungle, see a desert fortress made by humanity's most notorious empire, explore a city of identical castles, and examine a Greek isle's bloody history from the air.

Peek at landmarks in places where they shouldn't be. Wing your way over an imperial pyramid in the Netherlands, a massive metal sphere in remote Russia, a lion shape carved into an English hillside, and a bare swath cut through an Austrian forest.M

Examine strange relics forgotten by time. Visit a perturbing circle of stone in the Golan Heights, a mountain of headless statues in Turkey, a castle left to crumble in the Saudi Arabian desert, and a time-worn secret in the wilds of Peru.

Confront objects that make no sense. Spot a spinning island in an Argentinian marsh, a colossal triangle stuck in the Arizona desert, mysterious multicoloured pools across northern Ethiopia, and a huge human figure hidden in the Australian outback.

Take a deep dive into watery enigmas. Glide over a sunken Italian city, a unique underwater cemetery in the Florida Keys, a yellow brick road to nowhere in the depths of the North Pacific, and puzzling rocky constructions off the coast of Australia.

Feast your eyes on divine designs. Circle around psychedelic swirls in the Utah wastelands, see a bizarre configuration of circles in the Sahara, uncover hidden lines with the help of a drone, and swoop down over a remote polka-dot lake in Canada.

Tower over amazing metropolises. Learn why an important urban centre is sinking toward oblivion, soar over sprawling ruins buried under Saharan sands, learn the modern secret of an ancient fortress, and eye a ghost town on the edge of the Gobi.

Get petrified by cryptic rock structures normally hidden from view. Look inside curious dwellings in the Peruvian Andes, visit a sacred monolith in Wyoming's Black Hills, haunt a Turkish stone village, and spot an immovable waterfall in Mexico.

Witness jaw-dropping animal spectacles from high above the Earth. Watch a whirling herd of northern nomads, see undersea behemoths show off in the Pacific shallows, track a US porcine stampede, and confront top ocean predators on the Florida coast.