Urban photographer Roman Robroek spent five years scouring the continent for the grandest examples of forgotten architectural beauty. Here: Watch your step on this Polish spiral staircase. (Photo by Roman Robroek/South West News Service)

Norway's Karsten Warholm celebrates winning the men's 400m hurdles at the Diamond League in London, July 21, 2018. (Photo by Andrew Boyers/Action Images via Reuters)

RAF Tornados fly above the Lossiemouth air base on March 18, 2011 in Lossiemouth, Scotland. UK defence forces will help to enforce a no-fly zone over Libya after the UN voted in favour of a resolution that backed 'all necessary measures', except a foreign occupation force, to protect Libyan civilians.

In this handout image provided by the City of New York, a Nissan NV200 is seen as a New York City taxi cab in New York City. The Taxi and Limousine Commission along with New York City Mayor Michael Bloomberg announced the Nissan NV200 designed by Nissan North America, Inc., has been chosen as the winner of the Taxi of Tomorrow competition and will become the City's exclusive taxicab for a decade. (Photo by City of New York via Getty Images)

Homeless people queue to get free hot food organized by social services during frost winter day in-Kiev on December 18, 2012. Nineteen people died of exposure in Ukraine in the last 24 hours amid temperatures of minus 20 degrees Celsius (minus 4 degrees Fahrenheit), bringing the toll this month to 37, the health ministry said Tuesday. (Photo by Sergei Supinsky/AFP Photo)

Participants wearing superhero costumes attend the World DC Comics Super Heroes event in San Martin de Valdeiglesias, near Madrid, April 18, 2015. To celebrate the anniversary of the publication of the very first Superman story, DC Comics are asking fans to help set a new world record for the largest global gathering of people dressed as DC Comics Super Heroes. (Photo by Andrea Comas/Reuters)

Nepalese women performs ritual as they take a holy bath in the Bagmati River, during the Rishi Panchami festival, in Kathmandu, Nepal September 18, 2015. Rishi Panchami is observed on the last day of Teej when women worship Sapta Rishi (Seven Saints) to ask for forgiveness for sins committed during their menstrual periods throughout the year. The Hindu religion considers menstruation as a representation of impurity and women are prohibited from taking part in religious practices during their monthly menstruations. (Photo by Navesh Chitrakar/Reuters)

In this October 18, 2015 photo, contestant Carlos Angevil, Miss Gay Vargas, competes in the swimsuit category of the ninth annual Miss Gay Venezuela beauty pageant in Caracas, Venezuela. Miss Gay Venezuela requires contestants be younger than 37 and be at least 1.7 meters (5' 6" feet) tall. (Photo by Ariana Cubillos/AP Photo)