On the western side of Mount Hood lies the longest glacier cave system in the contiguous United States. In 2012, these caves were mapped to a combined length of 7,166.8 feet by cave explorers Brent McGregor and Eddy Cartaya. Currently, the total passage length is hundreds of feet less. Glaciers are frozen rivers; they are always moving and changing... (Photo and caption by Josh Hydeman)

A homeless man rests on the side of a street at the old quarter of Yemen's capital Sanaa November 27, 2015. (Photo by Khaled Abdullah/Reuters)

A man smiles as he carries firewood he bought on a street amid ongoing fuel and cooking gas shortages in Yemen's capital Sanaa December 2, 2015. (Photo by Khaled Abdullah/Reuters)

Competitors release their hens during the World Championship Hen Racing Championships in Bonsall, Britain August 1, 2015. (Photo by Darren Staples/Reuters)

In this photo provided by the RSPCA/Australian Capital Territory, an overgrown sheep found in Australian scrubland is prepared to be shorn in Canberra, Australia, Thursday, September 3, 2015. The wild, castrated merino ram named Chris, yielded 40 kilograms (89 pounds) of wool – the equivalent of 30 sweaters – and sheded almost half his body weight. (Photo by RSPCA ACTvia AP Photo)

A gannet grabs a fish by its beak, 2014, in Shetland, Scotland. Hundreds of gannets crash into the sea in search of food – leaving a trail of air bubbles in their wake. Richard Shucksmith, 41, on the Shetland Isles, Scotland captured the remarkable scene as he took a boat to feed the large colony of seabirds that nested on the cliffs. The photographer has taken images of the gannets every summer for the last three years as the birds gather on the cliffs to breed. (Photo by Richard Shucksmith/Barcroft media)

“Eclipse is a luxury motor yacht constructed by Blohm + Voss in Hamburg, Germany. Its exterior and interior were designed by Terence Disdale Design and its naval architect was Francis Design. The yacht was delivered to Russian businessman Roman Abramovich on 9 December 2010”. – Wikipedia

Photo: The Eclipse, reported to be the largest private yacht in the world, is viewed docked at a pier in New York on February 19, 2013 in New York City. The boat, which measures 557ft in length and is estimated to cost 1.5 billion US dollars, is owned by Russian billionaire Roman Abramovich and arrived into New York on Wednesday. (Photo by Spencer Platt)

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.