Singer Rihanna performs onstage during the 2011 Billboard Music Awards at the MGM Grand Garden Arena May 22, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images for ABC)

(L-R) Natalie Burns and Taunia Arave battle as referee Nick Stevens (R) looks on during the US National Sumo Championships at the Riviera Hotel & Casino June 24, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

Singers Steven Tyler (L) and Nicole Scherzinger perform onstage at the iHeartRadio Music Festival held at the MGM Grand Garden Arena on September 24, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images for Clear Channel)

“El rio mas bonito del Mundo”, the most beautiful river of the world, the “River of five colors”, the “Rainbow River”, or even the “Escaped from Paradise”, are the shimmering appellations that Colombians give to Cano Cristales, a small stream located in the heart of the Macarena National Park, 150 km (93 miles) south of Bogota. Photo: A waterfall is seen at the end of the rainy season, in August, when the water level finally decreases, in the Cano Cristales RIver in the Sierra de la Macarena in Colombia. It has become covered with a bright pink endemic aquatic plant, Macarenia Clavigera. (Photo by Olivier Grunewald)

Filipinos riding on makeshift carts cross over an overflowing dam during a downpour in Las Pinas city, south of Manila, Philippines, 05 September 2017. According to the latest forecast from the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) state weather bureau, typhoon signals were raised over Northern Luzon brought by a tropical storm (local name: Tropical Storm Kiko) and warned fisherfolks and small seacrafts not to venture onto the sea due to big waves. (Photo by Francis R. Malasig/EPA/EFE)

People pause at a memorial set up for victims of a mass shooting in Las Vegas, Nev., on Tuesday, October 3, 2017. A gunman opened fire on an outdoor music concert on Sunday. It was the deadliest mass shooting in modern U.S. history, with dozens of people killed and hundreds injured, some by gunfire, some during the chaotic escape. (Photo by John Locher/AP Photo)

Television personality Farrah Abraham (C) enjoys adult entertainment as she hosts the VIP Back Door Key party at the Crazy Horse III Gentlemen's Club on August 4, 2017 in Las Vegas, Nevada. The newly launched VIP membership program offers patrons exclusive entrance to the club through the back door. (Photo by Bryan Steffy/WireImage)