Ice Age · 20,000 years ago
What you're walking through
20,000 years ago, at the coldest point of the last ice age, sheets of ice up to 3 km thick covered much of North America. South of the ice stretched cold, dry grassland dotted with spruce and birch: the mammoth steppe.
Its giants grazed in the open: mammoths, horses and bison, with saber-toothed cats, lions and dire wolves waiting for them. People were there too, newly arrived. Within a few thousand years, the climate warmed and most of these animals were gone.
Who lives here
Woolly mammoth
About 3 m tall at the shoulder · plant eater · 400,000 to 4,000 years ago, northern Eurasia and North America
A thick coat, small ears and long curved tusks for sweeping snow off the grass. Our ancestors hunted them and painted them on cave walls.
Saber-toothed cat
Smilodon · up to 280 kg · meat eater · 2.5 million to 10,000 years ago, the Americas
Heavier than a lion, with canines up to 28 cm long. It ambushed large prey and held it down with powerful forelegs before the killing bite.
Giant ground sloth
About 3 m long, 1 tonne · plant eater · died out at the end of the last ice age
A cousin of today's tree sloths the size of a bear, walking on its knuckles. It reared up on its hind legs and tail to pull down branches.
The trees are simple stand-ins for Ice Age spruce and birch, and the animals are stylized low-poly models.
How to walk
Press Start walking above. WA SD or the arrow keys move you, the mouse looks around, Shift runs and Space jumps. Look at an animal to see what it is. Esc pauses, and M turns the sound on or off. You're invisible: nothing here can see you.
Other times
4 billion years ago
Early Earth
Lava fields and smoking volcanoes, under falling meteors and a huge Moon. Nothing is alive yet.
150 million years ago
Late Jurassic
Conifer forests and ferns, with Apatosaurus herds and Stegosaurus.
70 million years ago
Late Cretaceous
Flowering trees and palms, with T. rex, Triceratops and Parasaurolophus.