Mysterious parallel microtunnels discovered in rock defy geology and could be the work of unknown microscopic ancient life.

Rocks in Australia preserve evidence that plates in Earth’s crust were moving 3.5 billion years ago, a finding that pushes back the beginnings of plate tectonics by hundreds of millions of years.

Prehistoric engravings of giant snakes along South America’s Orinoco river are among the largest examples of rock art we know of anywhere in the world, with some stretching for more than 40 metres.