America’s Haunts, a trade association, estimates there are 1,200 for-profit haunted attractions in the U.S. plus another 3,000 haunted houses operated by charities that open for only a day or two every year. The commercial attractions collectively bring in from $300 million to $500 million annually. Fright Nights attendees make a turn through one of four haunted houses at this year's spooking season setup at the South Florida Fairgrounds. This house is named The Smiths and was created by Craig McInnis. (Photo by The Palm Beach Post)

Uranjargal, a leader of the Mongolian neo-Nazi group Tsagaan Khass, stands next to a statue of Chingunjav, a Mongolian national hero, in Ulan Bator June 22, 2013. The group has rebranded itself as an environmentalist organisation fighting pollution by foreign-owned mines, seeking legitimacy as it sends Swastika-wearing members to check mining permits. Over the past years, ultra-nationalist groups have expanded in the country and among those garnering attention is Tsagaan Khass, which has recently shifted its focus from activities such as attacks on women it accuses of consorting with foreign men to environmental issues, with the stated goal of protecting Mongolia from foreign mining interests. This ultra-nationalist group was founded in the 1990s and currently has 100-plus members. (Photo by Carlos Barria/Reuters)

“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

Two life-size Victorian style dolls shocked Londoners morning December 3, 2015 as the creepy pair popped up at commuter hotspots across the capital to mark the launch of the world's first psychological theme park ride created by Derren Brown, coming to Thorpe Park Resort in 2016. (Photo by Matt Alexander/PA Wire)

A Sikh devotee carries on over-sized religious sword during a religious procession to celebrate the birth anniversary of the first Sikh Guru or master, Sri Guru Nanak Dev Ji, the founder of Sikhism in Amritsar, India, 05 November 2014. The birth anniversary of Guru Nanak Dev Ji will be observed on 06 November. (Photo by Raminder Pal Singh/EPA)

Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)