source : http://www.boston.com
For well over a hundred years, people have hopped on bicycles for transportation, recreation, competition, and more. In many parts of the world, spinning pedals moves goods and generates electricity. While usually attached to two wheels, pedal power takes many forms, adapting to a wide range of needs. Globally, over 100 million bicycles are produced every year - over 60% of them in China - easily doubling world production of automobiles. Efficient, clean, and cheap, pedal power in all its forms can solve modern problems with basic technology, and offers a health benefit to those cranking away. And it's hard to beat the simple joy of riding a bike. Gathered here are images of people around the world as we pedal for a reason, or just because. -- Lane Turner
A boy rides his bicycle near rice fields in Bago, Myanmar on February 20, 2012. (STR/AFP/Getty Images) 
Team Spain competes in the men's team pursuit qualifying during the 2012 UCI Track Cycling World Championships at Hisense Arena on April 4, 2012 in Melbourne. (Mark Dadswell/Getty Images) # 
Men pedal a bicycle crank pump to refuel cars at the site of a gas station in the earthquake- and tsunami-destroyed town of Minamisanriku, Japan. (David Guttenfelder/Associated Press) # 
A rebel with a bicycle celebrates the liberation of al-Qawalish, Libya, after six hours of battle. Smoke rises from a power station shelled by retreating government soldiers. (Gaia Anderson/Associated Press) # 
Congolese boys push a Chikudu (wooden bicycle) as they transport goods to the market of Mushaki, Democratic Republic of Congo on December 4, 2011. Chikudus are as much a source of local pride as they are a part of the local economy. Formal jobs are rare here, and crafting chikudus is a skilled and prestigious occupation. Chikudus are the brainchild of desperate improvisation. Before they overtook the dusty foot paths and rocky roads of eastern Congo, men carried produce to market in wheelbarrows. No one is certain when chikudus were invented, or by whom, but locals agree they appeared after independence from colonial Belgium in 1960. By then bicycles and motorcycles had reached Congo, and chikudu makers tried to replicate their functionality. (Simon Maina/AFP/Getty Images) # 
A major snow storm brought blizzard conditions to the Boston area on January 12, 2011, but it didn't interrupt Marvin Wang's bike commute. (Dina Rudick/Globe Staff) # 
Indian schoolgirls ride on a bicycle rickshaw during a break in the monsoon rains near the Jama Masjid mosque in New Delhi on August 5, 2011. (Kevin Frayer/Associated Press) # 
Mechanical Engineer Daniel Ratner demonstrates the StreetView Trike used as a mapping resource by the StreetView team at Google in Mountain View, Calif. on April 12, 2011. Ratner created the prototype for the bicycle. (Marcio Jose Sanchez/Associated Press) # 
Dutch-speaking Leon Zoetebier (right) and French-speaking Franz Coquidor bicycle in opposite directions in the streets of Brussels on January 27, 2011 to highlight Belgium's problems bridging the gulf between the Dutch-speaking north and French-speaking south. (Georges Gobet/AFP/Getty Images) # 
Acrobats stack themselves up on a bicycle during a celebration for the new year in Beijing on December 31, 2011. (Liu Jin/AFP/Getty Images) # 
A woman rides on the handlebars of a bicycle as she takes part in May Day protests organized by the Occupy Toronto and the No One Is Illegal groups in Toronto on May 1, 2012. (Mark Blinch/Reuters) # 
A Thai man rides with his son on a custom-built tricycle designed for floodwaters in Bangkok on October 28, 2011 as the Chao Phraya river coursing through the capital swelled to record highs. (Aaron Favila/Associated Press) # 
Paul Reubens, in character as Pee-wee Herman, arrives via bicycle on water to receive the Visionary Award at the 2011 Scream Awards on October 15, 2011 in Los Angeles. (Chris Pizzello/Associated Press) # 
Biological analyst Alan Dowden of the Seattle Sperm Bank rides the Sperm Bike, a custom-designed, high-tech bicycle used to deliver donated sperm to fertility clinics in Seattle on November 8, 2011. (Anthony Bolante/Reuters) # 
One of many Velomobiles, recumbent bicycles with sleek, colorful outer shells, heads for the open road in Portland, Ore. on July 28, 2011. Twenty five riders rode to Washington D.C. to spread the message that sustainable, clean transportation can be fun. (Rick Bowmer/Associated Press) # 
An employee of Japan's Murata Manufacturing Co. presents the company's bicycle-riding robot "Murata Seisaku-kun" at an electronics show in Chiba, Japan on October 4, 2011. (Kim Kyung-Hoon/Reuters) # 
An elderly Chinese man rides his micro-bike in Beijing on October 22, 2011. (Mark Ralston/AFP/Getty Images) # 
Zhang Yali tests a giant bicycle designed and made by him and his friends in Jilin, China on December 25, 2011. The bike weighs over a ton. (China Daily/Reuters) # 
German bike designer Dieter "Didi" Senft, aka El Diabolo during the Tour de France, presents his latest bicycle invention, the so-called '111-twelve-teeth-rake-bicycle' in Storkow, Germany on March 12, 2012. The bicycle is made of 111 garden rakes. (Patrick Pleul/AFP/Getty Images) # 
A young visitor admires a model of a solar bicycle on display at the 2011 Taipei World Design Expo on October 22, 2011. (Patrick Lin/AFP/Getty Images) # 
A man lies on the ground surrounded by candles to symbolize cyclists being hit by vehicles during an annual cycling tour in honor of bikers killed in road accidents in Mexico City on May 18, 2011. 24,000 cyclists die in road accidents throughout Mexico each year. (Jorge Dan Lopez/Reuters) # 
Cyclists take part in the "World Naked Bike Ride" in Sao Paulo on March 10, 2012. The event aims to defend the right of cyclists to ride on the streets in safety. (Nacho Doce/Reuters) # 
Cyclists wear costumes on the 13th Tour of the Fireflies in suburban Pasig, Philippines on April 17, 2011. The event aimed to promote environmental awareness and push bicycle riding as a means to minimize pollution. (Aaron Favila/Associated Press) # 
Cyclists stand behind their foldable bicycles as they prepare to ride along Victoria Harbour in support of a new cycle path in Hong Kong on December 17, 2011. (Antony Dickson/AFP/Getty Images) # 
Pickwick Bicycle club members stand near Charles Dickens' birthplace on February 7, 2012 in Portsmouth, England to celebrate the bicentenary of his birth. (Peter Macdiarmid/Getty Images) # 
A man rides a bicycle carrying boxes of expanded polystyrene in downtown Shanghai on July 26, 2011. (Carlos Barria/Reuters) # 
A man rides his bike on the frozen river Elbe in Dresden on February 2, 2012. (Robert Michael/AFP/Getty Images) # 
A woman rides a bicycle in Amsterdam on February 3, 2012. Temperatures plunged to new lows in Europe where a week-long cold snap claimed more than 222 lives. (Robin Utrecht/AFP/Getty Images) # 
A fruit vendor on a bicycle travels next to people on motor scooters in Ho Chi Minh City on April 3, 2012. (Nick Ut/Associated Press) # 
A man admires an art work entitled "Forever Bicycles" by Chinese dissident artist Ai Weiwei at the Taipei Fine Art Museum on October 28, 2011. (Sam Yeh/AFP/Getty Images) # 
An employee looks out of a window of a bicycle shop and rental station, which has been decorated with some one hundred old bikes on April 6, 2011 in Altlandsberg, Germany. (Patrick Pleul/AFP/Getty Images) # 
South Africans light up a Baobab tree by riding bikes in Durban on November 30, 2011 as part of a renewable energies display. (Alexander Joe/AFP/Getty Images) # 
A girl cycles on a power generating bike at the Occupy camp in Finsbury Square on February 29, 2012 in London. (Peter Macdiarmid/Getty Images) # 
Students practice sight-reading while riding exercise bikes in the Conestoga Elementary school in Gillette, Wyo. on November 22, 2011. Students are free to take a turn doing their assignments on one of the six stationary bikes in the back of the room. (Reiley Wooten/Gillette News Record/Associated Press) # 
Tourists ride an ice sled as they visit Zizhuyuan Park in Beijing on January 3, 2012. (China Daily/Reuters) # 
Mike Montgomery falls from his bike during the best trick event at a winter games event on February 11, 2012 in Vail, Colo. (Daniel Petty/The Denver Post/Associated Press)# 
Green Bay Packers players make their way to NFL football training camp on bikes on July 30, 2011 in Green Bay, Wis. The ride is a tradition with the team, as players borrow children's bikes and ride with the kids to practice. (Morry Gash/Associated Press)# 
Felix Girola waves to people as he takes his self-made bicycle for a spin through downtown Havana on May 18, 2012. Girola says his bike measures 11 feet tall. (Franklin Reyes/Associated Press)# 
Double amputee private Steve Richardson demonstrates his adapted bike as members of the Help For Heroes team of wounded service personnel who will compete in the Race Across America this June is announced at Tedworth House on April 20, 2012 in Tidworth, England. The team will cycle 3051 miles across 12 states and cover a distance which is 30 percent longer than the Tour de France, but complete it in roughly half the time. (Matt Cardy/Getty Images)# 
100-year-old cyclist Robert Marchand of France gets on his bike to set a world record for cycling non-stop for one hour at the Union Cycliste Internationale (UCI) velodrome in Aigle, Switzerland on February 17, 2012. Marchand, born November 26, 1911, cycled 24.251 km (15 miles) around the 200 meter indoor track to set the record. (Denis Balibouse/Reuters)# 
A competitor negotiates a wallride during the Valparaiso Cerro Abajo urban downhill mountain bike race in Valparaiso, Chile on February 19, 2012. (Eliseo Fernandez/Reuters)# 
Riders battle in a chariot race at Chariot Wars during a three-day Mini Bike Winter Olympics on February 18, 2012, in Portland, Ore. Armed, variously, with all manner of foam-padded apparatus, teams battled for the “Ben Hurt” trophy. (Rick Bowmer/Associated Press)# 
Canadian cyclist Ryder Hesjedal (right) and Spanish rider Joaquim Rodriguez ride on Passo dello Stelvio on the 20th stage of the Tour of Italy (Giro d'Italia) on May 26, 2012. Hesjedal became the first Canadian to win the Giro. (Daniele Badolato/AFP/GettyImages)# 
A man dressed as the Easter Bunny rides a Velib public bicycle in Paris on April 5, 2012. (Benoit Tessier/Reuters)# 
Models practice with their bicycles for London Fashion Week in London on February 17, 2012. (Leon Neal/AFP/Getty Images)# 
A couple on a bicycle coast down a hill past farm fields outside the eastern coastal city of Wonsan, North Korea on October 6, 2011. (David Guttenfelder/Associated Press)# 
A boy rides on the back of a bicycle amid dense fog on a cold morning in Lahore on January 18, 2012. (Mohsin Raza/Reuters)# 
Children ride their bikes across Fishing Creek on April 3, 2012 in Rupert, Pa. (Jimmy May/Bloomsburg Press Enterprise/Associated Press)# 
A cyclist rides his bike at a skateboard park on May 22, 2012 in Austin. (Eric Gay/Associated Press)#
