Dina Rudick

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 (49 photos total)
A boy rides his bicycle near rice fields in Bago, Myanmar on February 20, 2012. (STR/AFP/Getty Images)

April 22 will mark Earth Day worldwide, an event now in its 42nd year and observed in 175 countries. The original grass-roots environmental action helped spur the Clean Water Act and Clean Air Act in the United States. Gathered here are images of our planet's environment, efforts to utilize renewable alternative sources of energy, and the effects of different forms of pollution. -- Lane Turner and Leanne Burden Seidel (35 photos total)
A ladybug in flight spreads its wings as it flutters from grass blade to grass blade at Rooks Park in Walla Walla, Wash. on April 2, 2012. (Jeff Horner/Walla Walla Union-Bulletin/Associated Press)

Seemingly strange weather patterns continue to break high and low temperature records. The same patterns spawned an early tornado season in the midwestern United States and brought late season snowstorms to the west. Record snow falls and frigid temperatures characterized a particularly difficult winter across Europe with many deaths attributed to the conditions. Signs of Spring for the Northern Hemisphere (which began officially with the Vernal Equinox - March 20 - when the hours of day are approximately equal to the hours of night) like trees blossoming and flowers blooming, the shedding of winter coats and the desire of anyone -who has spent an all too long winter season indoors - to venture outside to soak up the sun. -- Paula Nelson (45 photos total)
Cherry blossoms of the Japanese Yoshino variety bloom along the Tidal Basin, March 19, 2012, in Washington, DC, with the Jefferson Memorial to the rear. This season celebrates the 100-year anniversary of the gift of the cherry trees from Japan to Washington, DC. (Paul J. Richards/AFP/Getty Images)