Technicians check a CRH high-speed train at Shanghai Hongqiao High-speed train base on December 28, 2011 in Shanghai, China. China's railway stations have started today to sell tickets for the 2012 Spring Festival travel season scheduled to run between January 8th and February 16th, centred around the Chinese New Year which this year falls on January 23rd. (Photo by ChinaFotoPress/Getty Images)

Smokes rises from a fire as a Palestinian protester takes cover during clashes with Israeli troops near the Jewish settlement of Beit El, near the West Bank city of Ramallah October 9, 2015. (Photo by Mohamad Torokman/Reuters)

A Fulton Hotshot lights a controlled burn on the so-called “Rough Fire” in the Sequoia National Forest, California, August 21, 2015. In California, suffering its worst drought on record, about 2,500 people were forced to flee Christian camps east of Fresno at Hume Lake as the so-called Rough Fire crossed Highway 180, officials said. (Photo by Max Whittaker/Reuters)

Civilians are led by members of pro-Russian self-defence units as they run outside a military base during an assault in the Crimean town of Belbek near Sevastopol March 22, 2014. Russian troops forced their way into a Ukrainian airbase in Crimea with armored vehicles, automatic fire and stun grenades on Saturday, injuring a Ukrainian serviceman and detaining the base's commander for talks. (Photo by Vasily Fedosenko/Reuters)

A Russian daredevil has captured a vertigo-inducing selfie – while standing on top of a Dubai skyscraper. Nineteen-year-old Alexander Remnev scaled the Princess Tower – the worlds tallest residential building at 1,350ft – before getting his camera out to take these stomach-churning pictures. Photo: He leans on the very top of the tower as he takes this vertigo-inducing picture. (Photo by Alexander Remnev/Caters News)

The Zhangjiajie National Forest Park is a unique national forest park located in Zhangjiajie City in northern Hunan Province in the People's Republic of China. It is one of several national parks within the Wulingyuan Scenic Area.

The Mexico – United States barrier – also known in the United States as the border fence, rotted fence or border wall – is actually several separation barriers designed to prevent illegal movement across the Mexico – United States border.