Too often, man-made structures mar the landscape around them. A factory cuts a harsh silhouette against a once-picturesque riverbank; a gaudy hotel sprawls onto an otherwise pristine beach. But somehow, bridges do the opposite. Instead of detracting from the view, they enhance it.
A valley that you might have overlooked on its own is suddenly breathtaking with a gleaming white bridge spanning it; an uninspiring river becomes grand when traversed by an elegant steel structure. Add to that the engineering prowess that goes into building them, and bridges become destinations in and of themselves.
We've rounded up 10 of the most remarkable examples here, along with insider tips on how best to experience them.
Tallest: Millau Viaduct, France
Not long ago, Millau -- a provincial town set between two limestone plateaus in the South of France -- was known for little more than its traffic jams. Every July and August, the village would become jammed with travelers en route to their summer vacations in Spain. But thanks to the Millau Viaduct, the town is now home to one of the country's major tourist attractions.
Seventeen years in the making, from the first sketches in 1987 to the final touches in 2004, the Millau Viaduct is an architectural feat in more ways than one. Sure, it is held up by the highest pylons in the world (803 feet high) and has the highest road-bridge deck in Europe (886 feet). But, most importantly, it reaches 1,125 feet at its highest point, making it the tallest bridge in the world (for reference, New York's Chrysler Building is only 1,046 feet tall).
Impressive stats, to be sure, but it's the bridge's visual effect that has the most impact. Gleaming white and ultra-sleek, it cuts a striking figure against the green valley below and the blue skies above.
Best Vantage Point: Millau Viaduct is closed to pedestrians, but if you're a runner you can sign up for La Course du Viaduc de Millau, a 14-mile race that crosses the bridge. Barring that, hop in a car. The bridge was designed with a slight curve, so you can see it in its entirety just before you cross over. course-viaducdemillau.org.
Widest: Sydney Harbour Bridge, Australia
Measuring 160 feet across, this suspension bridge has room for eight lanes of traffic, two railroad tracks, a pedestrian walkway, and a bicycle path. A bit much? Not when you consider that the bridge connects Sydney's business district with the residential North Shore, making it the primary route for the city's commuters.
A bridge built to accommodate such volume would seem a modern-day creation, but Sydney Harbour Bridge opened back in 1932 -- it will celebrate its 80th birthday in 2012.
Best Vantage Point: On the walkway at the eastern side of the bridge, you'll find the entrance to the Pylon Lookout, a tower with some of the best views of Sydney and the harbor. As you climb the 200 stairs to the top, stop on each of the three levels to check out the exhibits on the history of the bridge. pylonlookout.com.au, $11.
Longest: Danyang-Kunshan Grand Bridge, China
When it comes to bridges, China doesn't mess around -- the country is home to 11 of the world's 15 longest. Three of the top five bridges are part of the Beijing-Shanghai High-Speed Railway, a $33 billion project that will nearly double the capacity of the route to 80 million annual passengers.
Opened to the public in June 2011, the Danyang-Kunshan Grand Bridge ranks as the world's longest. It stretches an astonishing 102.4 miles -- that's longer than the distance between New York City and Philadelphia!
Best Vantage Point: This is a railroad bridge, so the only way to experience it is by hopping aboard the train. Thankfully, the high-speed rail travels up to 186 mph, cutting what used to be a 10-hour trip to a much more manageable five hours. trains.china.org.cn, from $89 one way.
Most Traffic: George Washington Bridge, New York
Last year, 51 million cars, buses, and trucks traveled eastbound across the George Washington Bridge, which connects Manhattan and New Jersey over the Hudson River. Every one of New York City's 8 million residents would have to cross the bridge over six times to hit that number.
Fortunately, the bridge is built to accommodate this kind of record-breaking activity, with a total of 14 lanes of traffic (eight on the upper level, six on the lower level). Of course, this statistic only takes into account motorized vehicle traffic.
If you count absolutely everything that crosses the bridge, the unofficial winner is the Howrah Bridge in Kolkata, India. The eight-laner is traversed by an estimated 80,000 vehicles, as many as 1 million pedestrians -- and countless cows each day.
Best Vantage Point: There are additional lanes on either side of the George Washington Bridge for pedestrians and cyclists, but that puts you too close to the action to get a good view. Instead, take the Circle Line's Full Island Cruise, a three-hour tour that circles the entire island of Manhattan and passes under seven bridges, including the George Washington Bridge.
Boats leave throughout the day, but hold out for an evening departure so you'll be able to see the bridge lit up against the night sky. circleline42.com, $36.
Longest Suspension: Akashi Kaikyo (or Pearl) Bridge, Japan
Imagine an iconic bridge (the Golden Gate, for example), and chances are you've thought of a suspension bridge. These elegant structures are formed by literally "suspending" the road deck from steel cables strung between towers.
This style will never measure as far as other types -- viaducts like the Danyang-Kunshan Grand Bridge are supported from below by pylons and can thus stretch as long as needed—but suspension bridges rank among the lightest, strongest, and most beautiful bridges in the world.
At nearly four times the length of the Brooklyn Bridge, Japan's Akashi Kaikyo Bridge (also known as the Pearl Bridge) is the clear winner in this category. With three connected spans -- two at 3,150 feet and one at 6,532 feet -- the Pearl stretches a total of 12,831 feet across the Akashi Strait from the cosmopolitan port city of Kobe to Awaji Island (which, not coincidentally, is the hub of Japan's pearl industry).
Japan gets hit with extreme weather conditions, and this bridge, completed in 1998, was built to withstand them all, including winds up to 179 mph and earthquakes up to 8.5 on the Richter scale. But that doesn't mean this bridge isn't a beauty: In addition to its connection to the Japanese pearl industry, the bridge gets its nickname from the lights on its cables, which are said to resemble a strand of colorful pearls at night.
Best Vantage Point: From the Kobe side of the bridge, take an elevator to the Maiko Marine Promenade. The 984-foot tubular observation deck offers views of the strait, the bridge's interior, and Osaka Bay.
Most Photographed: Golden Gate Bridge, California
With its trademark "international orange" paint, its picturesque surroundings, and the daily rolling in of the morning fog, it should come as no surprise that the Golden Gate Bridge is said to be the most photographed in the world.
David Crandall, assistant professor of informatics and computing at Indiana University, thinks the numbers back up this claim. In a recent study, he tracked text tags for nearly 35 million images on Flickr to determine which world sights were shot the most.
While other bridges -- namely London's Tower Bridge, Florence's Ponte Vecchio, and New York's Brooklyn Bridge -- were close runners-up, two simple facts gave the San Francisco structure a winning edge: geography and size.
The City of Hills has so many vantage points -- and the bridge is such a looming presence in the skyline -- that the Golden Gate manages to sneak into scores of photos, even when it's not the intended subject. Trying to take a shot of the Presidio? The harbor? The city skyline? There's a good chance the Golden Gate might make an appearance, whether as the main focal point or just a happy accident.
Best Vantage Point: At Kirby Cove, in the Marin headlands north of the city, you get the trifecta: a spectacular view, a healthy dose of nature, and no crowds.
To get there from Highway 101, take the last exit for Sausalito and follow Conzelman Road until you reach the parking area on the left. From there, walk down the steep dirt path lined with eucalyptus and cypress trees until you reach the cove.
Longest Covered: Hartland Covered Bridge, New Brunswick, Canada
When the Canadian government was being wishy-washy about whether or not to build a bridge across the St. John River, a group of private citizens took matters into their own hands. They formed the Hartland Bridge Company and opened the 1,282-foot-long bridge in 1901. Five years later, in what had to be a vindicating we-told-you-so moment, they sold it to the government, who took over all maintenance.
Though covered bridges are now seen as quaint and old-fashioned, the icon's construction was not without its share of controversy. Shelter made sense in terms of weather -- snow and ice are a sure thing throughout the winters here -- but the public worried it would encourage risqué behavior among the town's youth.
In the end, it was covered, and perhaps their fears were warranted: Legend has it, men would train their horses to stop halfway across the bridge so they could sneak in a kiss before crossing over to the other side.
Best Vantage Point: There's something about a covered bridge that demands you take it slow. Rather than speed across in a car, take the walkway that was added in 1945.
Most Bricks Used to Build a Bridge: Goltzsch Valley Bridge, Germany
At 1,860 feet long, or about one third of a mile, the Goltzsch Valley Bridge in the eastern German state of Saxony may seem like a minor player in the bridge world. But the length isn't what sets it apart; it's the material.
At a time when most bridges were built with stone or metal, this one was built with bricks -- 20 million of them. It would be an odd (and costly) choice of material in most places, but in this area of Saxony, where there were several large clay deposits, it was an economical one. In fact, it's thanks to those same clay deposits that the second-largest brick bridge in the world, the Elster Valley Bridge, is also in Saxony; it's a quaint counterpart, made with only 12 million bricks.
Best Vantage Point: Take the autobahn to the town of Mylau, and follow the signs to the bridge from there. You'll find a designated parking lot, but don't stay there. Instead, take the path on the left-hand side just before the lot. It will lead you to a meadow, where you'll get spectacular views of the bridge.
Longest Footbridge: Walkway Over the Hudson State Historic Park, New York
When this 6,767-foot-long steel cantilever railroad bridge opened in 1889 over the Hudson River, it ranked as the longest bridge in the world. It carried trains across the river for 85 years until a fire damaged the tracks in 1974, forcing it to close.
Thirty-five years later, after several false starts at restoration, a nonprofit group called Walkway Over the Hudson reopened the bridge, this time as a pathway for pedestrians and cyclists, in October 2009. Now a state historic park, the Walkway Over the Hudson is the longest footbridge in the world, serving as a link between trails on both sides of the river for walkers, runners, cyclists, and rollerbladers.
Best Vantage Point: In the fall, the leaves turn the banks of the Hudson into a collage of reds, oranges, and yellows. Picnic on one of the tables at either end of the bridge before strolling across, giving yourself plenty of time to snap photos along the way. walkway.org.
Oldest: Caravan Bridge, Turkey
At first glance, there's nothing remarkable about this bridge. The arched stone slab straddling the River Meles, in Izmir, Turkey, extends only 42½ feet and is about as simple as they come.
But it's the age, not the physical aspects, of the Caravan that sets it apart. Built in 850 B.C., the bridge is 2,861 years old and has reportedly been crossed by the likes of Homer and Saint Paul. As impressive as some of the other bridges on this list are, it's hard to imagine they'll last even half that long.
Best Vantage Point: Located in old Izmir, the bridge is best reached by taxi. Simply ask your driver to take you to "Sarnic," which is the Turkish name for the bridge. We recommend going during the afternoon, when the light is best for photography.