The Gateway Arch: Everything You Need to Know About the Tallest Monument in the US

Photo: Getty Images/Kubrak78

There’s hardly a more recognizable landmark in the Midwest than the Gateway Arch in St. Louis, a monument honoring Thomas Jefferson and his ideas for America’s westward expansion. Reaching 630 feet into the air, it’s the tallest monument in the United States and the tallest arch in the world. Designed by the American Finnish architect Eero Saarinen, the arch was an engineering feat—in fact, many people thought it would fall over. But as a testament to the architects, engineers, and workers who built it, the Gateway Arch has long stood the test of time. “The Arch has always been one of the world’s most significant architectural marvels and an iconic symbol of that midcentury era,” says architect Jason Cadorette, senior associate at Cooper Robertson, which worked on a refurbishment project at the arch in 2018. Here’s everything you need to know about the Gateway Arch.

The Gateway Arch at a glance

The iconic Gateway Arch is the defining feature of Gateway Arch National Park in St. Louis. “The Gateway Arch represents St. Louis as the ‘Gateway to the West,’” says Pam Sanfilippo, program manager of Museum Services & Interpretation at Gateway Arch National Park. It was designed by architect Eero Saarinen, who won a competition for the project. You can plan your visit at nps.gov/jeff.

Where is the Gateway Arch?

The riverfront Gateway Arch is located in downtown St. Louis, Missouri; it’s situated on the bank of the Mississippi River, representing the westward expansion of the United States.

How tall is the St. Louis Gateway Arch?

The arch is 630 feet tall and 630 feet wide. Since you’re not always looking at the arch straight on, you experience an illusion that it’s much taller than it is wide.

What is inside the Gateway Arch?

The Gateway Arch is more than just a monument, it’s also a striking observation deck. A tram system takes visitors to the very top offering views of the greater St. Louis area. The legs hold stairs, but these aren’t accessible to the public and only used in emergencies or for maintenance. Underground is a visitors center.

History of the Gateway Arch

In 1935, President Franklin D. Roosevelt signed an executive order to establish the Jefferson National Expansion Memorial in the city of St. Louis, as a national monument for “Thomas Jefferson’s vision of a unified continental nation and St. Louis’s role as a confluence and gateway to the American West during the 1800s,” says Sanfillippo. But the Gateway Arch itself came much later.

A design competition for the monument was announced in 1945. “It gave liberty to designers to design whatever best expressed the memorial’s theme,” says Sanfillippo. “Eero Saarinen’s arch was unanimously chosen out of 172 entries.”

Who built the gateway arch?

Eero Saarinen was the designer of the Gateway Arch. The acclaimed Finnish American architect is best known for his structures like the TWA Flight Center in New York and the main terminal at Dulles International Airport outside of Washington, DC, as well as furniture designs like the iconic Tulip chair and pedestal table. “The Gateway Arch is such a perfect expression of Saarinen’s sculptural approach, and with the museum and surrounding grounds it also embodies modernism’s goal of integrating landscape design, art, and interior design with architecture,” says Cadorette.

When was the gateway arch built?

Construction began in 1963 and was completed in 1965, and it opened to the public in 1967. But that wasn’t the end of the design story for the Gateway Arch.

“One of the important points to recognize about this architectural history is that Saarinen actually died two years before construction began on the arch itself, so in many ways, his full vision was never realized,” says Cadorette. “The grounds were cut off from the rest of St. Louis by a highway, the museum ended up becoming something of an afterthought, and the landscape plan was not built out in the way its designers had intended.”

Architecture firm Cooper Robertson brought to life some of that original vision through a $380 million refurbishment that saw the restoration of the base, the renovation and expansion of the museum and visitor center at the Gateway Arch, and a “total rework of the landscape and park grounds that directly connects the Arch to downtown St. Louis for the first time,” explains Cadorette, who worked on the project. The refurbishment was completed in July 2018.

When did the Gateway Arch Become a National Park?

Technically, the park itself has been a unit of the National Park Service (NPS) since its inception in 1935. But the arch hadn’t been built yet! “Once Saarinen’s design was chosen and constructed, the park quickly became known as the St. Louis Arch or the Gateway Arch,” says Sanfilippo. “Following the CityArchRiver project completion in 2018, public support grew for changing the park’s name to Gateway Arch National Park. Congress approved the name change in 2018.” She adds that it’s the smallest park with a ‘national park’ designation by the NPS with a footprint of just 91 acres.

Design Details of the Gateway Arch

“What looks like a single, smooth, shimmering piece of sculpture is in fact a very mathematically complicated and painstakingly constructed stack of steel triangles,” says Cadorette. The Gateway Arch—which takes the shape of a catenary curve, or the curve formed by a chain held at two fixed points—was built using the “keystone-in-place” method of construction. Each leg was built independently from smaller, prefabricated parts and joined at the top by a single piece called the keystone. “The arch is fabricated from stainless steel panels, supported by a carbon steel framework which uses triangle cross-sections. As the arch rises up, the structure narrows from 54 feet at the base to 17 feet at the apex,” says Alan Berman, founder and principal of Archetype Architecture.

Welders had to work extraordinarily carefully to ensure their measurements were precise. If off by as little as 1/64th of an inch, they would not have been able to join the arch at the top. Though these workers were sure of their product, many people speculated that the arch would fail when the keystone was set in place to join the legs. It didn’t, of course. “The arch stands as an exemplification of Saarinen’s ability to meld engineering and architecture to create pure forms,” says Berman.

Interesting Facts About the Gateway Arch

1. Forty blocks of St. Louis were demolished to build the arch and its surrounding park

In what St. Louis city engineer W. C. Bernard called “an enforced slum-clearance program,” dozens of warehouses and cast-iron buildings housing 290 businesses were razed to create space for the arch. It was a controversial move—particularly since it was discovered that the vote to allocate city funds to the project was rigged.

2. The insurance company for the project predicted that 13 workers would die during construction

With a difficult construction process that saw people working hundreds of feet in the air with no safety nets, it’s not too much of a surprise that the insurers expected there to be fatalities. But somehow, no one died during construction. The only death associated with the Gateway Arch was that of Kenneth Swyers, who in 1980 leaped from a plane, parachuted to the top of the arch, and attempted to BASE-jump to the ground. His auxiliary parachute didn’t deploy, and he fell to his death.

3. There was confusion over whether Eliel or Eero Saarinen won the design competition for the monument

Both father (Eliel) and son (Eero) entered the competition, and even though Eero was chosen as the winner, confused officials mistakenly told Eliel he had won. The architects and their family had already had a Champagne celebration to toast the senior Saarinen when a telegram came in to correct the error.

4. The unique tram system was invented by a man with no formal engineering training

Thanks to the curved shape of the arch, a regular elevator couldn’t bring visitors from the base to the top. Saarinen’s firm called the Montgomery Elevator Company in Moline, Illinois, to solve the problem. Dick Bowser, a college dropout whose family was in the elevator business, happened to visit a friend who worked at the company, and that friend connected him with the architect. Bowser was asked to design the system in just two weeks. His solution was a tram that was part elevator and part Ferris wheel—it’s the very system that lifts visitors to the observation deck at the top of the Gateway Arch today.

And for those who can’t take the tram ride in person, you can still take a virtual peek inside the Gateway Arch. “Improving accessibility and helping people of all abilities experience the full impact of the Arch was an important goal for the project, so we also created a virtual experience with a live webcam feed for those who aren’t able to physically travel on the tram cars,” says Cadorette.

5. Presidents aren’t allowed to go to the top—except President Eisenhower

The Secret Service has forbidden all presidents from ascending the Gateway Arch due to security concerns—it is, after all, a very tight, enclosed space. The only exception was Dwight D. Eisenhower, who signed the order for the construction of the arch in 1954. In 1967, when he was 77 years old, the former president visited St. Louis to give a speech. A trip to the top was not in his itinerary, but when he showed up early to the monument (after it had closed to the public), he insisted on riding the tram up.

Originally Appeared on Architectural Digest