Oxford Scientific
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Reuters/Aly Song
X-ray: NASA/CXC/SAO/Ákos Bogdán; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare & K. Arcand
Richard Drew, File/Associated Press
Gary Hershorn/Getty Images
ARMADA DE COLOMBIA
NurPhoto
More than 50 billion shoes are made every year. The biggest manufacturers, like Nike, Adidas, and Asics, make them durable enough to run hundreds of miles. But this also makes them incredibly expensive and difficult to recycle.