Cairo — seen here at center in an image from the International Space Station — and Lagos, Nigeria, would register more than 2 million fewer deaths this century if emissions of carbon and other gases were cut. (NASA/NASA)

When dinosaurs roamed Earth, the planet looked like . . . what, exactly?

Scientists have plenty of theories about how the planet changed over time. Continents split. Water receded. Mass extinctions wiped out some forms of life and helped fuel others.

You can’t go back in time to see it in person, but the Ancient Earth Globe is a good substitute. The website gives you views of the planet as it looked over the eons, starting 600 million years ago. You can jump back and forth between, say, the point at which the first multicellular life appeared and the time that the dinosaurs went extinct.

Helpful summaries break down what was going on at different stages, such as the Late Ordovician period 450 million years ago, when the first coral reefs emerged. But the most fun part is spinning the globe itself and watching the unfamiliar continental and oceanic formations of times past.

Sick of looking at long-lost Earth? You can click over to the Dinosaur Pictures and Facts website at dinosaurpictures.org, which is associated with the Ancient Earth Globe.

The site pulls its information from PaleoDB, which draws upon decades of paleontology and submissions from hundreds of scientists. True to its name, the dinosaur site contains images and facts about a massive number of dinos.