Girls fit their skirts before ballet class at the Ballet Santa Teresa academy in Rio de Janeiro, Aug. 13, 2012.

A girl has her hair fixed before ballet class at the Ballet Santa Teresa academy in Rio de Janeiro, Aug.13.

Youths perform during ballet class at the Ballet Santa Teresa academy in Rio de Janeiro, Aug. 13.

A girl performs during ballet class at the Ballet Santa Teresa academy in Rio de Janeiro, Aug. 15.

Afghan skateboarding school students skate along a street on the third annual 'Go Skateboarding Day' organized by the 'Skateistan School' in Kabul, Afghanistan on June 21.

An Afghan student performs at the skateboarding school on the third annual 'Go Skateboarding Day' organized by the 'Skateistan School' in Kabul, Afghanistan on June 21..

Afghan students perform at their skateboarding school on the third annual 'Go Skateboarding Day' organized by the 'Skateistan School' in Kabul, Afghanistan on June 20. 'Skateistan' is Afghanistan's first co-educational skateboarding school. Operating as an independent, neutral Afghan NGO, the school engages growing numbers of urban and internally-displaced youth in Afghanistan through skateboarding, and provides them with new opportunities in cross-cultural interaction, education and personal empowerment.

A baby giant African pouch rat is rewarded with a banana by its trainer after accurately finding a dummy mine during a training exercise at the grounds of a pioneering Belgian NGO in Morogoro, Tanzania on October 27, 2010. Light, with an acute sense of smell and easily motivated by food rewards, these kind of rats have been found to be highly effective in mine detection. It takes two human deminers a day to clear a 200 square-metre (2,150 square-feet) minefield, but if they work with two rats they can sweep it in 1.5 hours. So far they have helped re-open almost two million square metres of land

A baby giant African pouch rat is is watched by its trainer as it learns to correctly identify the scent of tuberculosis in sputum samples during a training exercice at the grounds of a pioneering Belgian NGO in Morogoro, Tanzania on October 27, 2010.

A baby giant African pouch rat is carried in a cage by its trainer at the main grounds of the center.

A baby giant African pouch rat sits on the shoulder of the Bart Weetjens, the founder of APOPO, the Belgian NGO that's teaching the rats to smell out landmines.