Panama Canal Fossils Reveal Ancient Collision of Worlds

Entire hillsides are being blasted away to widen the Panama Canal. It was the biggest event in our planet's history since the extinction of the dinosaurs. Three million years ago, the Americas collided.

The creation of the Panama Isthmus - the narrow land bridge that joins the two continents - wreaked havoc on land, sea and air. It triggered extinctions, diverted ocean currents and transformed climate.

Now a multi-billion dollar project to widen the Panama Canal is set to reveal new secrets about the event that changed the world. Panama is a tiny country, but in a perfect location. Positioned just north of the equator in the Caribbean, its famous canal is the strategic hub of the global shipping industry.

The 80 km (50 mile) long Panama Canal, completed in 1914, connects the Atlantic and Pacific Oceans. Its existence means that ships can avoid - at a price - the treacherous 8,000 mile journey round Cape Horn, the southernmost tip of South America.

Authorities hope that the canal will increase revenue from shipping. However, the massive excavations have also proved to be a "gold mine" for scientists, trying to uncover Panama's hidden past.

As entire hillsides are being blasted away to expand the canal, amazing fossils are emerging that shed light on this key event. However, scientists only have a short window to collect the fossils before they are re-buried beneath concrete.

One of those fossil hunters stumbled upon one of the most important discoveries so far: the jaw and bones of horses, rhinos and camels. Three million years ago there was a kind of land rush. Animals that were native to North America - sabre-toothed cats, horses, camels and elephants - surged south across the land bridge. Animals from South America such as giant sloths and armadillos, moved north.

Fossils hinted at the possibility that giant predatory birds dubbed "terror birds" seem to have migrated from between the Americas as early as five million years ago. It is possible that long before the seaway finally closed, a chain of islands spanned the gap. Perhaps Terror Birds and other animals were the original "island-hoppers," migrating from one island to the next.