Unearthing our past, fossil hunters, or paleontologists, trace the story of life on Earth - bone by bone.
Fossils are the remains or impressions left behind by plants or animals that lived thousands of years ago.
A fossil forms when organic matter is quickly covered by sediment - often carried in water or preserved in permafrost.
Protected from decomposition and scavengers, the organic material is slowly replaced by minerals and the fossilized sample preserved.
But fossils aren't just a load of old bones.
Fossils can be shells, skin and tissue, ancient plants, such as ferns, and seeds or whole organisms such as dinosaurs or trees, many meters long and weighing many tons.
Preserved remains of animals or plants
Take hundreds to millions of years to form
The relative age can be deduced by observing where the fossil was found.
The fossils in the lower layers of rock are older than fossils in the upper layers.
By comparing fossils, paleontologists can observe how plants and animals have changed, or evolved, over millions of years, as they adapt to survive the changes in the world around them.
This paleontologist is analyzing an early dinosaur fossil from the southern hemisphere.
His specimen has a bulge in the top of the leg bone, whereas those from the north have no bulge.
This shows how - as the landmasses of early Earth shifted and split - animals isolated on different landmasses evolved differently in response to changing habitats.
A series of minute physiological changes like this - taking place over millions of years - eventually gave rise to new types of dinosaurs.
Fossil evidence tells us how existing and extinct species evolved over time.
And this knowledge is set in stone - all in the fossil record.