By the start of the 1860s, the dream of a railroad stretching from the Atlantic to the Pacific had existed for at least 20 years.

Entrepreneurs and visionaries promoted the concept in speeches and pamphlets.

Even as train disasters took hundreds of lives, people called on Congress to fund the ambitious project. But it wasn't until the nation descended into civil war that progress was made.

President Abraham Lincoln signed the Pacific Railway Act into law, greenlighting the

construction of a transcontinental railroad. Two railroad companies were charged with building it,

and those two companies turned the project into a great race, sort of.

Overseeing the construction from east to west was the Union Pacific Railroad,

but from the jump, Thomas Durant, the man who controlled the Union Pacific,

saw it as a way to line his pockets.

When construction finally began in earnest in December 1865, he purposely mismanaged routes and supplies,

as well as exaggerated the threat of Native American attacks as part of his scheme to siphon federal funds.

But out in California, the other railroad company, the Central Pacific, took the race seriously.

Construction had started on time in 1863 in the Sacramento area.

Two years later, the railroad faced its most daunting challenge.

In the summer of 1865, the Central Pacific Railroad was preparing to tackle the imposing, cathedral-like chain of mountains called the Sierra Nevada's.

But in order to make it into the heart of the mountain range, the railroad needed to overcome Cape Horn.

Cape Horn was essentially a small mountain that rose 1,400 feet above the floor of the

American River Canyon. It was mostly covered with pine trees and brush, but in some places,

it was smooth, bare rock. It was nearly vertical, with no natural ledge for tracks.

The railroad couldn't detour around it.

If the line was going to continue east, the crew would have to carve directly into the

cliffside.

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