Emily Hasler, an English Heritage employee at Charles Darwin's home, Down House, cleans a rabbit bone in his old study on April 2, 2011 in Downe, England. Staff at the house are cleaning and preparing the property ahead of their peak visitor season. The house contains the study where Darwin wrote “On the Origin of Species”, as well as family rooms and an extensive garden that inspired the renowned scientist. (Photo by Oli Scarff/Getty Images)

Thoughts. They fly through the broad expenses of our mind, floating gracefully in midair, going into the clouds, and then reemerging once again. Some are quick and furtive, others are grand and majestic. We reflect upon them as they enter our minds, and once they leave, they are usually gone for good. However, some thoughts are different. These thoughts resemble a flock of angry birds or a swarm of hungry moths that invade your mind, slowly eating away at your sanity, strength, and desire to live. Such thoughts often plague that minds of people with Obsessive Compulsive disorder. They completely occupy their time; constantly there; ever-present. With his book sculpture, Thomas Wightman was able to accurately convey the way these thoughts consume the mind, slowly building a nest within it, resisting all attempts to drive them away.

Brazil's tallest teen is set marry her beau – despite him being over a foot smaller than her. Elisany da Cruz Silva (18) is a staggering 6ft 8ins (206 cm) tall while her compact fiancee Francinaldo da Silva Carvalho is only 5ft 4ins (162 cm). Despite a massive 1ft 4ins between them, Francinaldo had no problem increasing the distance by dropping to one knee after a romantic stroll along the beach. (Photo by Barcroft Media)

Artist Vik Muniz is known for his gigantic composite installations and sculptures created from thousands of individual objects. In this new collaboration with artist and MIT researcher Marcelo Coelho, Muniz takes the opposite approach and explores the microscopic with a new series of sandcastles etched onto individual grains of sand.

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.

Rose-ringed Parakeets roost in a copse in Wormwood Scrubs Park on December 6, 2011 in London, England. Approximately 2,500 parakeets roost in the copse at the centre of Wormwood Scrubs which has been designated by English Nature as an important site of natural significance. (Photo by Oli Scarff/Getty Images)

A youngster with the Miami Seaquarium Spring Break Campers group gets a chance to touch one of two loggerhead sea turtles that are prepared to be released back into the wild at Bill Baggs Cape Florida State Park after undergoing rehabilitation at Miami Seaquarium March 13, 2012 in Key Biscayne, Florida. (Photo by Joe Raedle/Getty Images)