It's January 12th, 1828, deep beneath the ground in southeast London.

Isambar Kingdom Brunel puffs on a cigar and watches his two laborers standing on a raised platform maneuver a long plank of wood into position.

They're 60 feet down, working on the first ever tunnel beneath the River Thames.

One of the youngest engineers on the project, 21-year-old Brunel, is eager to prove himself.

His father, Mark Isambard Brunel, is the project's chief designer.

But the younger Brunel doesn't want anyone to think he got his job because of that connection,

so he works 20-hour shifts, getting only a few hours of sleep every night.

Now, in the flickering gaslight, Brunel watches the workers hammer the plank into the roof of the tunnel.

It's dangerous work. Wooden boards like this form a protective shield that is the only

barrier between them and the River Thames above. But the men are tired. They've been working all night.

And from the tunnel floor, Brunel can see that something isn't right. The new board is askew and silt is trickling through the gap.

But before Brunel can warn them,

the torrent of gray water burst through the roof,

knocking the men off the platform.

Helping them to their feet, Brunel orders everyone out of the tunnel immediately.

He knows the breach is irreparable.

The only thing that matters now is getting away. They turn and wade through the water,

which is now gushing around their feet, and growing deeper every second. As fast as they can,

they head back toward the stairs. Then the flood douses the gas lights, and the tunnel is plunged into darkness.

Fear grips Brunel.

Groping through the waste deep water, he grabs at the scaffolding, lines the tunnel, and pulls himself along.

But the scaffolding is now being lifted by the churning water.

...