Top 10 most impressive engineering projects - Number 5 and 4

5. The Hoover Dam

The Hoover Dam

When I first visited The Hoover Dam in my early twenties, fresh out of college and full of the curiosity of a new engineer, I never would have imagined the impact the grandeur of this monument would have on my professional life.  This is not because at the time, Hoover Dam was the most impressive structure I had ever been on, but rather it is the story of how the structure came into existence and how it conquered once thought to be impossible obstacles.

To create the Hoover Dam the contractors had to divert the flow of the mighty Colorado River through tunnels dug inside the canyon walls. The tunnels were 56 feet  in diameter with a  combined length was nearly 16,000 feet.  Following the diversion, engineers had to construct a structure tall and strong enough to sustain future generations and keep the Colorado river under control.

When the Hoover Dam was completed in 1935, it was the world’s largest concrete structure and the largest electric producing facility.  Years later as I stood 736 feet above the river bed, I felt the power of the structure. What inspired me at that instant was the humbling realization that at one point, this structure was just an idea.

4. Boston Big Dig

Memorial Bridge, Interstate Highway I-93

Recognized as the largest, most complex, and technologically challenging highway project in the history of the United States, the Central Artery/Tunnel Project significantly reduced traffic congestion and improved mobility in one of America’s oldest and most congested major cities. In addition, it helped improve the environment, and established the groundwork for continued economic growth for Massachusetts and all of New England.

The project, which replaced Boston’s deteriorating six-lane elevated Central Artery (I-93) with an underground highway, two new bridges over the Charles River, extended I-90 to Boston’s Logan International Airport, and Route 1A, created more than 300 acres of open land and reconnected downtown Boston to the waterfront.