Mask

A civilian wearing a mask holds a Tunisian flag in Sidi Bouzid, central Tunisia, Tuesday, Dec. 17, 2013 to mark the third anniversary of the Tunisian uprising. Several political groups gather at the square where Mohamed Bouazizi's self-immolation on Dec. 17, 2010 triggered mass protests against social marginalisation and government corruption in Tunisia.

Aimen Zine/AP

A civilian wearing a mask holds a Tunisian flag in Sidi Bouzid, central Tunisia, to mark the third anniversary of the Tunisian uprising. Several political groups gather at the square where Mohamed Bouazizi’s self-immolation in December 2010 triggered mass protests against social marginalisation and government corruption

A Nepalese Hindu devotee dresses as a deity as he prepares to participate in festivities at the Shikali Temple during celebrations for the Shikali Jatra festival in the village of Khokana, on the outskirts of Kathmandu on October 10, 2013.  Local villagers, who normally do not celebrate the country's most famous festival of Dashain, celebrate the Shikali Jatra each year.

Prakash Mathema/AFP

A Nepalese Hindu devotee, dressed as a deity, prepares to participate in festivities at the Shikali Temple during celebrations for the Shikali Jatra festival in the village of Khokana, on the outskirts of Kathmandu, on Thursday

A demonstrator marches during a teachers protest demanding better working conditions and against police beating, on Monday night in Rio de Janeiro.

Christophe Simon/AFP

A demonstrator marches during a teachers protest demanding better working conditions and against police beating, late on Monday night in Rio de Janeiro.

A teacher helps her student put on a face mask due to the haze in Putrajaya

Bazuki Muhammad/Reuters

A teacher helps her student put on a face mask at a school in Putrajaya, outside Kuala Lumpur, on Wednesday. The Malaysian capital remains shrouded in haze, as the environmental crisis continues after a week of thick hazardous smog covered the country and its neighbour Singapore

A protestor wearing a mask with the colours of the Kenyan flag participates in a demonstration against lawmakers' salary demands outside the parliament buildings in the capital Nairobi, May 14, 2013. Kenyan police in riot gear fired teargas and water cannons on Tuesday to disperse about 200 protesters gathered outside parliament to demonstrate against lawmakers' salary demands. REUTERS/Thomas Mukoya (KENYA - Tags: SOCIETY POLITICS CRIME LAW TPX IMAGES OF THE DAY)

Thomas Mukoya/Reuters

A protestor wearing a mask with the colours of the Kenyan flag participates in a demonstration against lawmakers’ salary demands outside the parliament buildings in the capital Nairobi on Tuesday. Kenyan police in riot gear fired teargas and water cannon in attempts to disperse about 200 protesters.