The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

Gunung Leuser National Park is a national park covering 7,927 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after Mount Leuser (3,381 m), protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside the park. Together with Bukit Barisan Selatan and Kerinci Seblat national parks it forms a World Heritage Site, Tropical Rainforest Heritage of Sumatra.

Gohei Hayashi of Kyoto University is seen in side his movable eco and healing house, “Kujira (Whale) House” July 21, 2007 in Tokyo, Japan. The house is made from Japanese paper, bamboo and tatami mat. Hayashi has travelled 500 km from Japan's ancient city, Kyoto to Tokyo with his eco house to promote his house which can be placed both out inside and outside to provide a private space. The Kujira house is available at the price of 800,000 yen (roughly US$6600). (Photo by Koichi Kamoshida/Getty Images)

Like a scene from a fantasy movie, a dilapidated room that appears to have been literally ripped out of a building remains suspended in mid air above Nantes, France. Its walls were torn apart, revealing bricks below the plaster, and wood floors reveal the joists inside. The floating room is accessible via a ladder. The gravity defying surreal installation is the work of Argentinean artist Leandro Erlich. The large-scale piece, called “Monte-meubles – L’ultime déménagement” (literally - The Furniture Lift – The Ultimate Moving Out), was created for the biannual Le Voyage a Nantes, an art festival which turns the entire French city into an art gallery.

Visitors to Salisbury Cathedral stop to look at Sean Henry's sculpture Standing Man (2007) currently being exhibited in the Cloisters on August 2, 2011 in Salisbury, United Kingdom. The exhibition, “Conflux: A Union of the Sacred and the Anonymous”, features over 20 contemporary sculptures of dramatically different scales occupying vacant plinths and open spaces on both the inside and exterior of the iconic 13th century building. This exhibition brings to the Cathedral the biggest single group of polychrome sculpture since the Reformation and runs until the end of October. (Photo by Matt Cardy/Getty Images)

A demonstrator wears a mask during a protest inside the Bay Area Rapid Transit (BART) Civic Center station on August 15, 2011 in San Francisco, California. The hacker group “Anonymous” staged a demonstration at a BART station this evening after BART officials turned off cell phne service in its stations last week during a disruptive protest following a fatal shooting of a man by BART police. (Photo by Justin Sullivan/Getty Images)

A mushroom cloud dwarfs a row of skyscrapers in what looks like a devastating nuclear bomb detonation. But thankfully this is just a spectacular weather-front blasting in from the tempestuous Rocky Mountains near Denver, Colorado, USA. The unbelievable shot is just one of many of the city's skyline taken by photographer Greg Thow. The 49-year-old has also captured equally stunning shots of lightning blasts and arching rainbows – all from the comfort of his balcony. (Photo by Greg Thow/Barcroft Media)