Salvation Mountain Location: Niland, Calif. Year: 1984 This structure might look familiar to you if you've seen Sean Penn's 2007 film Into the Wild. Salvation Mountain and its creator, Leonard Knight, were both featured in Penn's film. Knight was 80 years old when he was forced to leave the mountain due to his failing health. He died two years later, and concerns have been raised about the preservation of his work now that its creator is no longer around. In any case, the mountain, made from straw, adobe, and thousands of gallons of paint, and covered in Christian messages, is a treasured work of Folk Art. The Grolier Club Location: New York Year: 1884 Established in 1884, The Grolier Club is the oldest bibliophilic club in North America that still exists. The New York City landmark is a vehicle to another time and place. Besides storing shelves of books and housing illuminating and peculiar cabinets of curiosities, the Grolier Club is host to exhibitions and public events. Sun Tunnels Location: Box Elder County, Utah Year: 1976 Nancy Holt aims to achieve a sense of permanence with her art, and so far her aim continues to be realized in the form of Sun Tunnels, a permanent installation that the artist completed in 1976. Sun Tunnels is made up of four 18-foot-long and 9-foot-wide concrete pipes that have been perforated to correspond with celestial constellations. The perforations also allow sunlight to pierce the tunnel when it gets dark. The spots of light create the illusion of a starry night sky. Bayou Bend Location: Houston Year: 1966 Houston philanthropist Ima Hogg named her former home Bayou Bend. The mansion was designed by John F. Staub and built between 1927 and 1928 for Ima Hogg and her brothers, but was only opened to the public in 1966. The house is made up of gardens that were meant to function as outdoor rooms for living in and entertaining. Bayou Bend is also a ma**ive treasure chest of about 4,700 antique American decorative arts objects, showcased in various period room settings. Back to Nature No. 3 Location: Frederiksvaerk, Denmark Year: 2011 Mikael Hansen created his first Land Art project in Denmark in 1983. Since then, he has been fascinated with Land Art as a form of artistic expression. He works with sculpture, indoor installations, painting, and mixed media. Back to Nature No. 3 is one of his installations set in the outdoors of Denmark. 21c Museum Hotels Location: Louisville, Ky., Cincinnati, and Bentonville, Ark. Year: 2006 21c Museum Hotel aims to integrate contemporary art into the everyday lives of their guests. The first 21c Museum Hotel started out as an initiative by art collectors Laura Lee Brown and Steve Wilson to revitalize Louisville. They boldly converted five abandoned warehouses into this charming boutique hotel, which houses impressive art installations. Since then, the art hotel chain has expanded to other cities. Broken Circle/Spiral Hill Location: Emmen, Holland Year: 1971 Broken Circle/Spiral Hill is Robert Smithson's only Land Art work in Europe. Visitors to the site walk through a sand quarry to the artwork. While many earthworks don't last, this piece has been restored and is also preserved Nancy Holt's film Breaking Ground: Broken Circle/Spiral Hill (1971–2011), which is screened for visitors to Smithson's site. Olana Location: Greenport, N.Y. Year: 1872 19th-century Hudson River School landscape painter Frederic Edwin Church lived at Olana with his family. The 250-acre historic estate is so spacious, it accommodates five miles of carriage drives, most of which are now pedestrian-use only. Olana features a Persian-style mansion filled with Church's sketches, studies, and paintings, in addition to a varied collection of decorative art objects from around the world. The historic site now offers art exhibits, guided house tours, and walking tours. Guests are also welcomed to hike, run, and walk their dogs while taking in the pastoral landscape. Double Negative Location: Overton, Nev. Year: 1969-70 Now one of the icons of American Land Art, Michael Heizer's Double Negative first began in Dec. 1969. The spectacular sculpture consists of 244,800 tons of sandstone and rhyolite, carved with two gouges made by dynamite and bulldozers. Facing one another, the gouges are aligned as if there is some kind of a continuous, negative form between them. Apollo Pavilion Location: Peterlee, Durham, England Year: 1955 This ma**ive structure was originally built as part of a social housing development program in the County Durham, England. British artist Victor Pasmore designed the new town of Peterlee around this abstract pavilion, an experimental move that became a local controversy. The imposing structure became a hangout for local youths, and soon attracted graffiti and vandalism, which angered the town's residents. Now it is an architectural marvel worth seeing. The Lightning Field Location: Western New Mexico Year: 1977 Around the mid-'70s, Walter de Maria conceived of an idea for a new installation. He wanted a site was level and remote but at the same time was situated in a region that experienced frequent thunderstorms. After five years of searching, he decided on an area in the New Mexico desert. From June to Oct. 1977, de Maria worked on The Lightning Field, an epic work of art comprised of 400 stainless steel bars vertically embedded in the desert floor. Each time lightning strikes the rods, a new, evanescent landscape is born out of nature and art. The Dan Flavin Art Institute Location: Bridgehampton, N.Y. Year: 1983 Maintained by the Dia Art Foundation, the Dan Flavin Art Institute in Bridgehampton is a former firehouse and church, which Flavin renovated from 1983 to 1988. Using factory-made fluorescent lights in standard lengths and colors, Flavin created neon structures and installations. Flavin's fluorescent lights inhabit spaces by illuminating them with eye-candy colors. The Dan Flavin Art Institute was opened to the public in 1983. It now contains nine of Flavin's iconic fluorescent light works, which date from 1963 to 1981. Elements Location: Green River, Utah Year: 2013 Andrew Rogers' Elements was completed in 2013. The installation is made out of four distinct columns (one of which is topped with 23-carat gold) to represent the four elements: Earth, Fire, Water, and Wind. Elements is the second structure to have been added to the 75-acre sculpture park in Green River, Utah. The Brant Foundation Location: Greenwich, Conn. Year: 2009 The Brant Foundation, Inc., established in 1996, was founded by Peter Brant, who has ama**ed an expansive collection of contemporary American art over the years. In 2009, he opened the Brant Foundation Art Study Center in a converted stone fruit barn. The building was designed by architect Richard Gluckman. It aims to make works of art available and accessible for scholarly study. Most of the exhibitions at the Brant Foundation are long-term and curated primarily from the Brant Foundation's collection. Artpace Location: San Antonio Year: 1995 In 1995, Linda Pace, herself a San Antonio artist, founded Artpace in a former automobile showroom, which she converted into a high-tech studio. Artpace offers one of the best artist residencies, awarded by nomination, in which artists live and work for two months in the private apartments and studio spaces of this sleek facility. The artists are provided with technical support, a weekly stipend, and a hefty budget for supplies. The Mastaba Location: Abu Dhabi, UAE Year: Not yet built The images you see here are renderings of an upcoming project, titled The Mastaba, in Abu Dhabi. The idea for this project was first conceived in 1977 by the king and queen of large-scale installations, Christo and Jeanne-Claude. Once completed, The Mastaba will be the world's largest permanent sculpture. Designed to stand at 492-feet high, the imposing structure would tower over the Great Pyramid of Gaza. It will also be the artists' only permanent large-scale work. Prada Marfa Location: Valentine, Texas Year: 2005 Prada Marfa is a site-specific art installation by Berlin-based team Elmgreen & Dragset. The installation is made out of a biodegradable material and is meant to melt back into the earth. Located in the middle of the West Texas desert, the ironic installation mimics the appearance of a fully stocked Prada store. Recently, it was vandalized by an artist who covered the "store" in TOMS logos. Storm King Art Center Location: New Windsor, N.Y. Year: 1960 More than 100 ma**ive installations by major international artists are scattered around this 500-acre sculpture park, where art, place, and the natural world are in constant interaction with one another. You can go to a gallery or a museum whenever you want, but Storm King offers an interactive and fun experience with larger-than-life installations amid unforgettable scenery. Roden Crater Location: Flagstaff, Ariz. Year: c. 1979 Roden Crater is an extinct volcano northeast of Flagstaff, Ariz., that James Turrell managed to purchase in 1977 with funding provided by the Dia Art Foundation. Turrell converted the site into Light and Space Art installation. The Chinati Foundation Location: Marfa, Texas Year: 1979 The Chinati Foundation in Texas is a contemporary art museum founded by artist Donald Judd. Judd installed 100 of his untitled works in two former artillery sheds, which are situated at the center of the Foundation's permanent collection. Not unlike Roden Crater, the Chinati Foundation also emphasizes the inextricable link between art and its surrounding landscape. The permanent collection also houses works by Carl Andre, John Chamberlain, Dan Flavin, and Claes Oldenburg, among others.