New York Police Department tactical police officers stand guard near the New York Stock Exchange on September 9, 2011 in New York City. Officials are stepping up security in New York and Washington D.C. a day after U.S. officials received a credible but unconfirmed terror threat to utilize car bombs on bridges or tunnels in New York or Washington. (Photo by Justin Sullivan/Getty Images)

Polar bear twins make their first public appearance with their mother “Freedom” at Ouwehands Zoo Rhenen, in Rhenen, The Netherlands, 19 February 2015. The twins, who were born in November 2014, have not been named because their gender has not yet been determined. (Photo by Bart Maat/EPA)

Assi Mbengue nibbles as she prepares for the start of Las Palmas' Carnival Queen ceremony in Las Palmas, Spanish Canary Island of Gran Canaria, February 24, 2017. (Photo by Borja Suarez/Reuters)

Women perform a pole dancing routine during the national day celebration of “Urban Pole” dance along a street in Monterrey, Mexico, on June 9, 2013. (Photo by Daniel Becerril/Reuters)

In this February 19, 2017 photo, a statue of the Death Saint stands inside Mercy Church as Juan Carlos Avila Mercado gives a service, on the edge of Mexico City's Tepito neighborhood. “She chooses them and has always been with us”, said Avila, who says he is a Catholic priest, but who is not listed among the archdiocese's priests. “We are born and we die with death”. (Photo by Marco Ugarte/AP Photo)

Athletes in action during the international parachuting competition Mountain Gravity in Quinto, Switzerland, 27 August 2015. Some 200 participants from all over the world are expected to jump at the event running from 22 to 30 August 2015. (Photo by Samuel Golay/EPA)

A model poses at Checkpoint Charlie, a historic place in the German capital to promote the fashion magazine “Sous” on June 12, 2012. (Photo by Maurizio Gambarini)