Henderson Waves

Our world is full of wonders great and small, ancient and contemporary, natural and man-made. Here are 15 modern marvels that fill us with awe through the sheer scale, beauty, backbreaking effort and inspiration that brought them into creation. At 12 stories high, Henderson Waves is Singapore's tallest pedestrian bridge. It snakes across Henderson Road, connecting Mount Faber Park and Telok Blangah Hill Park. The bridge, which opened in 2008, is made of seven undulating curved steel ribs that alternately rise over and under its deck. The curved ribs form alcoves that function as shelters with seats within.

The Ledge at Willis Tower

Not afraid of heights? Check out the view from the Ledge at Willis Tower, formerly Sears Tower, in Chicago. The five-sided balconies, which opened in 2009, are suspended 1,353 feet in the air and jut out four feet from the building's 103rd floor Skydeck. They're actually more like boxes than balconies, with transparent walls, floor and ceiling. Visitors can see unobstructed views of Chicago from the building's west side, and a heart-stopping vista of the street and Chicago River below — if they're brave enough to look straight down.

Palm Jumeirah

Palm Jumeirah is an artificial island, the first and smallest of the three Palm Islands created off the coast of Dubai, United Arab Emirates. The palm-tree shaped island is so large that it can be seen from the International Space Station. It is currently home to luxury homes and the megaresort Atlantis, The Palm, and will eventually tout many other deluxe hotels. In the years since construction began in 2001, this island effectively has doubled the length of Dubai’s coastline.

Grand Canyon Skywalk

The Hualapai tribe of Arizona commissioned this horseshoe-shaped, glass walkway that opened above the Grand Canyon in 2007. The Skywalk juts off the rim of a side canyon 4,000 feet above the Colorado River. Despite the vertigo-inducing views, the glass bridge reportedly is very sturdy — it can support more than 71,000 pounds and can withstand gusts of wind over 100 mph.

Channel Tunnel

The Chunnel, as the 31.35-mile tunnel under the English Channel is known, opened in 1994, connecting Calais, France, with Folkestone, England. It is the second-longest tunnel in the world (behind Japan’s Seikan railway tunnel), and has the longest underwater section of any tunnel. The Eurotunnel Shuttle is a special vehicle transport train that has the largest rail cars in the world.

Three Gorges Dam

Located in China’s Hubei Province, this largest hydroelectric power station in the world contains a 375-mile-long reservoir within its impressive 7,661-foot concrete bulk. The scale of the controversial project is so huge that it has displaced millions of people, submerged hundreds of cultural sites in the Three Gorges area and precipitated an untold amount of damage on the regional environment. Construction began in 1994, but the dam is not expected to become fully operational until 2011.

Panama Canal

One of the most difficult engineering endeavors ever attempted, the Panama Canal is a 50.72-mile-long passage between the Atlantic and Pacific oceans that was begun by France in 1880 but completed by the U.S. in 1914. It drastically reduced shipping distances between New York and San Francisco, from 14,000 miles around Cape Horn to 6,000 when passing through the canal. During the American construction phase, 211 million cubic yards of dirt and rock were scraped away over 10 years to finish the canal.

Akashi-Kaiky┼Ź Bridge

Also known as the Pearl Bridge, this structure spans the strait between the islands of Honshu and Awaji in Japan. Upon its opening in 1998, the Pearl Bridge became the longest suspension bridge in the world, with a center span measuring 6,532 feet in length — making it a full quarter-mile longer than the previous record-holder. The entire three-span bridge is more than 12,000 feet long.

The Dreamliner

The Boeing 787 Dreamliner took off on its long-awaited first flight on Dec. 15, 2009. The Dreamliner is the first commercial airplane that’s mostly built from carbon-reinforced plastic. This composite material is light and strong and won’t corrode or be susceptible to metal fatigue. Using this kind of construction also reduces both the financial and environmental costs of building a new plane.

Hoover Dam

Visiting Las Vegas? Consider a side trip to Hoover Dam. It spans the Colorado River between Arizona and Nevada, about 30 miles southeast of Sin City. The massive dam, built between 1931 and 1936, is 726.4 feet deep, from foundation rock to the roadway on the crest of the dam. Hoover Dam generates, on average, about 4 billion kilowatt-hours of hydroelectric power each year for use in Nevada, Arizona and California — enough to serve 1.3 million people.

International Space Station

Orbiting Earth with a resident crew since November 2000, the International Space Station is accessible only to enterprising tourists who have bank accounts flush enough to afford approximately $25 million for the round-trip ticket offered by Space Adventures. To date, six space tourists have boarded the ISS to experience days of zero gravity orbiting the planet. However, that number is sure to rise in coming decades as private companies develop commercial spacecraft and programs to make the final frontier a viable travel destination.

Time Warner Center

This 750-foot tall skyscraper in New York City, which opened in 2003, consists of two towers bridged by an atrium containing upscale retail shops. It was the first major building to be completed in New York City after the Sept. 11, 2001, terrorist attacks. This “city in a building” contains the offices of Time Warner Inc., residential condominiums, and the Mandarin Oriental, New York hotel. Anderson Cooper 360° broadcasts live here from CNN Studios, and you’ll also find the 1,200-seat Jazz at Lincoln Center.

Millau Viaduct

The Millau Viaduct in southern France, which opened in 2004, is the tallest vehicular bridge in the world, with a roadway nearly 900 feet in the air. The cable-stayed design gives the bridge the appearance of a row of sailboats at sea, and the masts rise 1,125 feet — higher than the Eiffel Tower.

Oasis of the Seas

Royal Caribbean’s Oasis of the Seas made its debut in 2009 as the world’s largest cruise ship. It’s nearly five times the gross tonnage of the Titanic and 1 1/2 times longer than the U.S. Capitol building, has 16 decks and a capacity for 6,296 guests. The ship offers weeklong sailings in the eastern and western Caribbean. Cruises depart from Port Everglades in Fort Lauderdale, Fla.

Burj Khalifa

Dubai, United Arab Emirates, opened the world’s tallest skyscraper in January, 2010, and superlatives have poured in ever since. If you stuck the Eiffel Tower on top of the Empire State Building, you still wouldn’t have a structure as tall as the Burj Khalifa. It rises 2,717 feet from the desert and provides views of the Persian Gulf, the sail-shaped Burj al-Arab hotel and the man-made Palm Jumeirah island. Originally named Burj Dubai, the building was renamed in honor of Sheik Khalifa bin Zayed Al Nahyan, the ruler of Abu Dhabi, which pumped tens of billions of dollars into Dubai in 2009 as it struggled to pay enormous debts.