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)

A boat paddles behind a fence near a plane sitting on the flooded tarmack of the closed Don Muang airport November 3, 2011 in Bangkok,Thailand. The airport was used as a domestic terminal and was formerly the International airport. Thailand is experiencing the worst flooding in over 50 years and has affected more than nine million people. Over 400 people have died in flood-related incidents since late July according to the Department of Disaster Prevention and Mitigation. (Photo by Paula Bronstein/Getty Images)

Two helicopters are seen following a collision near Seaworld, on the Gold Coast, Australia, 02 January 2023. Four people are dead and another 13 injured after two helicopters collided before one crashed into the Broadwater on the Gold Coast. (Photo by Dave Hunt/EPA/EFE/Rex Features/Shutterstock)

Miss Georgia USA Emanii Davis, Miss Kentucky USA Kyle Hornback and Miss North Carolina USA Devin Gant competes in the swimsuit competition during the 2016 Miss USA pageant preliminary competition at T-Mobile Arena on June 1, 2016 in Las Vegas, Nevada. The 2016 Miss USA will be crowned on June 5 in Las Vegas. (Photo by Ethan Miller/Getty Images)

Brave slackliners have been pictured walking the ropes above Rio de Janeiro, Brazil on August 15, 2016, with the half a mile drop showing the city in all its glory. The stunning shots show the daredevils tread across an eighty-two-foot-long high line on Pedra da Gvea mountain with an amazing sunrise illuminating the city landscape behind. (Photo by Rafael Moura/Caters News Agency)

In this handout photograph received from the Delhi Police at the scene of the incident, an Indian schoolboy is confronted by a white tiger inside its enclosure at the Delhi Zoo in New Delhi on September 23, 2014. A white tiger on September 23 attacked and killed a schoolboy who appeared to have jumped or fallen into its enclosure at the zoo in the Indian capital, witnesses said. (Photo by AFP Photo/Delhi Police)

Mrs. Marie Graskamp of Milwaukee shows the different positions one might assume when entering the bomb shelter in Milwaukee September 3, 1958. This circular entrance is about three feet in diameter. This is the entrance (according to the builders) that would connect to the cellar of a home assuming the shelter was in the ground for added protection. If a bombing should occur, all members of family would proceed to the cellar and then through the circular port into the shelter. (Photo by AP Photo)