Women compare their bikini marks after sunbathing on a terrace to have the perfect bikini line (“marquinha” in Portuguese), at the Erika Bronze spa in Rio de Janeiro, Brazil, November 17, 2016. Women start arriving at the spa between 7am and 8am and will tan for approximately 3 hours. (Photo by Pilar Olivares/Reuters)

British Gas engineer Martin Caulfield, 69, services and cleans a gas lamp in front of Big Ben on October 31, 2011 in London, England. Caulfield has been looking after the traditional lights since 1982. There are still around 1600 left in the capital. (Photo by Matthew Lloyd/Getty Images)

A Pablo Picasso papier mache “huge head” mask, known as “Capgros” in Catalan, is displayed at the entrance of the “El Ingenio” shop on August 23, 2011 in Barcelona, Spain. “El Ingenio” (The Ingenuity) has been making and selling papier mache giant masks and huge heads for Catalan popular festivals since 1838. The “La Merce” festival will be held on September 24 to observe the feast day of Our Lady of Mercy, patron saint of Barcelona. (Photo by David Ramos/Getty Images)

Members of Japanese idol group Kamen Joshi (Masked Girls) in attires featuring images or names of U.S. President-elect Donald Trump, pose for a photo after their concert at their theatre in Tokyo's Akihabara district, Japan, December 12, 2016. (Photo by Toru Hanai/Reuters)

A Brazilian Navy member ejects spent cartridges while shooting rubber bullets during an exhibition of their operational capacity to combat terrorist attacks and riots ahead of the FIFA Confederations Cup and World Youth Day in Rio de Janeiro on May 27, 2013. (Photo by Ricardo Moraes/Reuters)

Participants wearing masks during a hazy day at the Beijing International Marathon in front of Tiananmen Square, in Beijing, October 19, 2014. (Photo by Reuters/Stringer)

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)