A New York window cleaner strapped to the side of The RCA Building in the Rockefeller Center, with St Patrick's Cathedral below him to the left. (Photo by William Lovelace/Express/Getty Images). 2nd May 1961

Window washers from the American National Skyline company (from left to right in the image below: Jordan Emerson, Steve Oszaniec and Danny Oszaniec) suit up as Marvel Comics superheroes to pleasantly surprise the children (who are patients) and their families inside as the dressed up crew cleans the outside of the windows at Le Bonheur Children’s Hospital in Memphis

Undulatus asperatus (or alternately, asperatus) is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. If successful it will be the first cloud formation added since cirrus intortus in 1951 to the International Cloud Atlas of the World Meteorological Organization. The name translates approximately as “roughened or agitated waves”.

“Getting to see girls’ bedrooms must have been a teenage obsession for the members of the all-male photographic collective Riverboom. Now that they have more or less grown up, they have decided to transform that dream into a reality. Riverboom’s Gabriele Galimberti and Edoardo Delille are traveling the five continents to see where girls, between the ages of 18 and 30, sleep. They have discovered that girls’ bedrooms are much more then just places where they lay down their heads – they are the places where girls read, love, dream, work and play”. – Gabriele Galimberti. Photo: Katerinai, 27 – Athens, Greece. (Photo by Gabriele Galimberti/Riverboom Ltd)

Beyonce performs during the Formation World Tour at Raymond James Stadium on Friday, April 29, 2016, in Tampa, Florida. (Photo by Frank Micelotta/Invision for Parkwood Entertainment/AP Images)

General view of a Saks Fifth Avenue Holiday shopping window display on November 30, 2015 in New York City. (Photo by Michael Loccisano/Getty Images)

Penitentes, or nieves penitentes (Spanish for “penitent-shaped snows”), are a snow formation found at high altitudes. They take the form of tall thin blades of hardened snow or ice, closely spaced with the blades oriented towards the general direction of the sun.

In this February 2, 2014 photo, people take pictures inside a cave at Apostle Islands National Lakeshore in northern Wisconsin, which has been transformed into a dazzling display of ice sculptures by the arctic siege gripping the Upper Midwest. (Photo by Brian Peterson/AP Photo/Minneapolis Star Tribune)