Fireworks explode over Elizabeth Tower housing the Big Ben clock in London. (Photo by Kirsty Wigglesworth/Associated Press)

A man dressed as a Santa Claus poses at the front of the Kollhoff Tower at Potsdamer Platz square in Berlin December 14, 2014. (Photo by Hannibal Hanschke/Reuters)

“Models decorated with glow-in-the-dark paint manage to stand out in a new series of pictures shot in the dark. Its well known that capturing beautiful photos without natural light is a tricky undertaking even for the most talented photographers but Hid Saib Neto has found a way to make the most of the darkness. The 26-year-old Brazilian photographer covered the group of models in neon paint before illuminating them with just a single ultra-violet light”. – Caters News. Photo: A model wearing the neon make up. (Photo by Hid Saib Neto/Caters News)

Undated David Yarrow handout photo of a gorilla as the self-taught wildlife photographer promotes his book, Encounter. (Photo by David Yarrow/Clearview/PA Wire)

Participants of the the goth festival “Wave Gothic Festival” walk in fancy costumes along the festival area in Leipzig, central Germany, Saturday, May 23, 2015. About 20,000 members of the scene are expected to attend one of the world's largest gothic and “dark” culture festivals until May 25, 2015. (Photo by Jens Meyer/AP Photo)

A dark Devon Rex cat is held by its owner during a competition in Bucharest, Romania, Saturday, September 26, 2015. More than 300 cats entered the international feline beauty competition in the Romanian capital. (Photo by Vadim Ghirda/AP Photo)

The bloodwood tree (Pterocarpus angolensis) is a deciduous tree with a high canopy, reaching about 15m in height and has dark bark. The red sap is used traditionally as a dye and in some areas mixed with animal fat to make a cosmetic for faces and bodies. It is also believed to have magical properties for the curing of problems concerning blood, apparently because of its close resemblance to blood. The name bloodwood for these trees stems from the dark red to brown sap that accumulates on wounds on the trunks.