"When I started, there was poop in bags everywhere," said Ricky Ojwang, skillfully navigating a rubbish-strewn canal in Mukuru, a Nairobi slum where he's worked to improve sanitation since 2012.

People taking part in "When Dreams Run Wild: Illuminated Parade" during the annual "Light Night Leeds" festival of visual arts in central Leeds in northern England. Light Night Leeds is an annual free multi-arts and light festival celebrating the diverse and thriving creativity of Leeds.

View of a wind farm near Diadema Argentina in the Patagonian province of Chubut, Argentina.

Visitors aboard "Trajineras" in Xochimilco, a network of canals and floating gardens that is one of Mexico City's top tourist attractions.

“Since I was very young, my mother kept telling me to be respectful to the elderly, especially those who were helpless."

Cattle breeders, indigenous teachers and loggers are among the more than 20 million people living in the Amazon in northern Brazil, carving out a living from the world's largest rainforest.

Visitors in traditional Korean hanbok dresses during a night opening at Gyeongbokgung Palace in central Seoul.

Thousands of people massed outside the Moulin Rouge caberet on Sunday night for a fireworks and French can-can extravaganza to mark the 130th anniversary of the storied Montmartre institution.

“A person wins the respect of people not because of his or her wealth or social status, but kindness and benevolence.”

Devotees with skewers pierced through their cheeks for purification taking part in a procession during the annual Vegetarian Festival in Phuket, Thailand. The festival begins on the first evening of the ninth lunar month and lasts for nine days.