A participant, riding a horse and dressed as a knight, presents flowers to women during an event marking Valentine's Day in central Moscow, Russia, February 14, 2016. (Photo by Maxim Zmeyev/Reuters)

A model backstage during day 1 of Aspen Fashion Week 2011 on March 13, 2011 in Aspen, Colorado.

Stefan Libon proposes to girlfirend Jess McGarrity in front of a banner message “Marry Me Jess?” on the deck of the Queen Mary 2, at Mrs Macquarie's Chair on Valentines day, February 14, 2012 in Sydney, Australia. (Photo by James Morgan/Carnival Australia via Getty Images)

A demonstrator is detained during May Day rallies in Santiago May 1, 2013. (Photo by Ivan Alvarado/Reuters)

Golden gate Bridge Fog Thick early morning fog engulfed a huge world famous bridge so that only the very tip of it is visible above the clouds. Photographer Ali Erturk, 33, hiked to the spot at 4am to capture the stunning sight of the Golden Gates bridge immersed in the dense swirls of fog. (Photo by Solent News and Photo Agency)