Human societies have always built great monuments to celebrate their values. The Egyptians had their pyramids. Medieval Europeans had their great cathedrals. For 20th century Americans, it was the skyscraper that best embodied the power and progress that defined their era.

Today, the undisputed king of American skyscrapers is the Empire State Building, the soaring Art Deco behemoth that opened its doors on May first, 1931, 75 years ago.

It is difficult to tell from the street at the base of the 381-meter tall Empire State Building how monumental a structure it really is. But you know it even before you ride its elevators to the top. In fact, as soon as you step inside the marble-clad lobby, with its Art Deco grillwork, fantastical chrome ornamentation and triumphalist artwork, it's clear this is a landmark, a building like no other in the world.

Lydia Ruth, the Empire State Building's public relations director, knows she has a world-famous treasure to work with. She points to the countless films in which it has played a leading role -- from King Kong to Sleepless in Seattle to An Affair to Remember, and Independence Day.

"When any movie or television show wants to say they are being filmed in New York and they do that establishing shot, they always show the Empire State Building," she says. "It's kind of like the spirit of New York."

In recent decades, the Empire State Building was eclipsed by the taller twin towers of the World Trade Center. After those towers were destroyed by terrorists in 2001, the Empire State Building was once again Manhattan's tallest spire. But the special quality of the building is about more than its height, or even its place in popular entertainment.

Ruth says she's just as impressed by the engineering, workmanship and sheer pluck that went into the building's construction. The Empire State Building was erected during the depths of the Great Depression, for most a time of gloom, not optimism and daring. Its construction was also a logistical tour de force that took a mere one year and 45 days to complete, a world record.

"I don't think you can get a piece of furniture made in a year and 45 days now," she says. "They actually installed a little rail line around the building to deliver the materials. We got marble from Italy; all the limestone came from one quarry in Indianapolis they still call the Empire State Building Quarry. They were good quality materials. There was no shoddy workmanship. And that's why I think it stands today as such a testament to engineering and people's ingenuity."

The Empire State Building, of course, is also a busy workplace, filled with travel agencies and photo studios, barber shops, garment factories and other enterprises. More than 850 tenants employ over 9000 people.

The most senior occupant is Jack Broad, 96, of the Empire Diamond Company on the 76th floor. He moved in in July, 1931, two months after the building opened, and has seen its best times and its worst times. He vividly recalls the day in 1945 when a B-25 bomber got lost in a fog and crashed into the 79th floor.

"The building became a torch," he says. "The gasoline ran down the side of the building. As soon as it burned out, the building looked intact -- except the plane was still sticking into the building."

Like many of the Empire State Building's loyal tenants, Broad says he finds great joy in the daily contact with the building and its unique vistas. "On a clear day, I can see for a hundred miles. People say 'when are you gonna retire?' I answer 'when they plant me.'"

The talk of height has made this reporter eager for the view from the top -- one of the only places in New York where one cannot see the Empire State Building.

In the classic elevator that takes one there, the operator sums up his job. "You want to know about here? I go up and down constantly, like a yo-yo. Right now, you are coming to the 102nd floor. This is the top of the world in New York! You can see everything!"

No postcard or film can prepare the visitor for the awesome 360-degree view from the Empire State Building's Observation Deck. It's a view enjoyed by an estimated four million tourists each year, all of them surely as wide-eyed as this group of visitors.

"It's spectacular to see the sights and be able to see the Statue of Liberty," says one American tourist. "It's pretty amazing," agrees a British visitor. "You've got the Chrysler Building and you've got Brooklyn Bridge, Central Park, the financial district."

Another tourist nods, grinning. "It's breathtaking. It shows you how big the world really is!"