Fair legacy: Greatest buildings from World's Fairs past
Travelers from around the world will converge on Milan in May to ruminate on the future of food at Expo 2015.
The event promises to put participants from 145 counties in touch with an estimated 20 million visitors across 60 pavilions, a record number exceeding even Expo 2010 in Shanghai.
Several buildings, such as the smog-eating Palazzo Italia pavilion, are already generating buzz -- and for good reason.
The World's Fair has left us with a number of familiar architectural marvels that long outlived their six months in the global spotlight.
With Expo 2015 now underway, we've put together a list of iconic structures purpose built for a World's Fair.
Eiffel Tower (Paris)
Gustave Eiffel expected a euphoric response when he announced that he'd build the tallest tower in the world for the 1889 World's Fair.
What he got instead was skepticism, virulent criticism and even protests "on artistic grounds."
History, however, would prove his critics to be a myopic crowd -- the Eiffel Tower has long outlived its 20-year expiration date.
It's not only the world's most visited monument (by ticket sales), but also one of its most valuable at 435 billion euros, according to a 2012 report, making it a crucial cog in the French economy and one of the most beloved sites in Europe.
The Ferris Wheel (Chicago)
When George Washington Gale Ferris Jr. unveiled his 264-foot-tall (80-meter) "pleasure wheel" at the 1893 Chicago World's Fair, it was the largest single piece of forged steel ever made.
It could fit 2,160 people, cost 50 cents to ride (twice the cost of the fair itself) and was so popular it saved the World's Fair from financial ruin.
Chicago's Ferris wheel was a direct response to Paris' Eiffel Tower, but while Gustave Eiffel's creation went on to become a beloved architectural marvel, Ferris' wheel would be churned out en masse.
The Space Needle (Seattle)
Seattle's 605-foot (184-meter) Space Needle was built at a bullish and forward-looking time in the United States.
It was 1962, the space race was on, and World's Fair organizers wanted to create something that would embody the era.
The resulting structure -- a compromise between designers Edward Carlson and John Graham, Jr. -- was a tower taller than any other west of the Mississippi River with an hourglass shape and UFO-like crown.
The Space Needle welcomed more than 2.3 million visitors during the Century 21 Exposition and has since become a symbol of the city, hosting more than 1 million visitors annually.
The Atomium (Brussels)
Another World's Fair icon that epitomizes an era is the Atomium, engineer Andre Waterkeyn's recreation of an iron crystal enlarged 165 billion times.
This multi-tiered structure unveiled in 1958, and inspired by the dawn of the Atomic Age, rises to a height of 335 feet (102 meters) and was meant to showcase Belgium's engineering might at Expo 58.
Dubbed one of Europe's most bizarre buildings, the structure's five habitable spheres are now part of a museum housing rotating installations and a restaurant with panoramic views.
The Biosphere (Montreal)
Montreal's towering 200-foot-tall (62-meter) geodesic dome was conceived by neo-futurist architect Buckminster "Bucky" Fuller -- the same man who popularized the term "Spaceship Earth" -- as a pavilion for the United States at Expo 67.
It was so popular at the 1967 event that it attracted 5.3 million visitors in the first six months.
It remained a top attraction on Montreal's Saint Helen's Island until a fire in 1976 destroyed the original acrylic membrane (though the steel frame remained).
Environment Canada purchased the site for $17.5 million in 1990 and turned it into an interactive museum with exhibits on climate change, eco-technologies and sustainable development.
Habitat 67 (Montreal)
Expo 67's other star attraction was an audacious model community and housing complex known as Habitat 67.
It was actually Israeli-Canadian architect Moshe Safdie's thesis for a masters in architecture at McGill University that miraculously got green-lit as an exhibition because of the way it jelled with the expo theme of "Man and his World."
The finished structure comprised of 354 identical, prefabricated concrete forms connected like Legos in an elaborate 12-story building with 146 residences.
Habitat 67 was touted as something that might redefine affordable housing and urban living, but its legacy has been something of a mixed bag.
Apartments in the co-op are now some of the most expensive in Montreal and the concept of prefabricated modular developments never really took off elsewhere.
The Magic Fountain of Montjuic (Barcelona)
It took the work of more than 3,000 people to turn the design of Carles Buigas into a real life "magic fountain" in time for the 1929 Great Universal Exhibition.
The spectacular showcase of color, light and motion was one of the world's first displays of water acrobatics, and remains as alluring today as it was nearly 90 years ago.
Music was first incorporated into the display in the 1980s, and performances today are set to everything from the soundtrack of "The Lord of the Rings" to "Barcelona" by Freddie Mercury.
Canada Place (Vancouver, British Columbia)
Canada Place received a royal launch from Prince Charles in 1986 when it debuted as the Canada Pavilion at Expo 86.
The flamboyant building along Burrard Inlet became an instant icon for Vancouver, with its signature roof of fabric sails designed by Toronto-based firm Zeidler Partnership Architects.
These days, Canada Place houses Vancouver's World Trade Centre, the Pan Pacific Vancouver Hotel and the Vancouver Convention Centre.
It's also the main cruise ship terminal for Canada's Pacific Coast, where many cruises to Alaska originate.
China Pavilion (Shanghai)
The China Pavilion became the largest display in the history of the World's Fair, welcoming a staggering 17 million visitors at Expo 2010.
The $220 million building, designed by septuagenarian He Jingtang, resembles an ancient Chinese crown, and draws inspiration from the Chinese ding vessel, used by emperors to make offerings to the gods.
The 206-foot-tall (63-meter) pavilion was converted into the China Art Museum in 2012, with five floors of modern Chinese art and a revolving roster of visiting exhibitions from some of the world's top galleries, like the Whitney in New York and the Rijksmuseum of Amsterdam.
The Statue of Liberty (New York)
The Statue of Liberty may not have been purpose-built for the World's Fair, but her scattered body parts were star attractions of the 1876 Centennial Exhibition in Philadelphia and the 1878 Exposition Universelle in Paris.
Her right arm (the one with the torch) debuted in Philadelphia, while her bust made its first appearance in the garden of Paris' Trocadero Palace, with other finished limbs nearby in the Champs de Mars.
All 200 parts of designer Frederic Auguste Bartholdi's long overdue statue didn't make it to New York until 1885, and Lady Liberty officially opened to the public in October 1886 as a symbol of friendship between the United States and France.