Lake Baikal is the world's oldest lake, at 25 million years (possibly older), and deepest, averaging 744.4 metres (2,442 ft).

Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the world, containing roughly 20% of the world's unfrozen surface fresh water.

“A balancing rock, also called balanced rock or precarious boulder, is a naturally occurring geological formation featuring a large rock or boulder, sometimes of substantial size, resting on other rocks, bedrock or on glacial till. Some formations known by this name only appear to be balancing but are in fact firmly connected to a base rock by a pedestal or stem”. – Wikipedia

Photo: “The Brimham Rocks are balancing rock formations located on Brimham Moor in North Yorkshire, England. The rocks stand at a height of nearly 30 metres in an area owned by the National Trust which is part of the Nidderdale Area of Outstanding Natural Beauty”. – Wikipedia. (Photo by Tee Time Tony)

“Hey! I'm Thomas Shahan, an artist and macrophotographer from Oklahoma. In my spare time over the past few years, I've been shooting portraiture of local arthropods. Why would I devote countless hours to tramping through forests, fields and the like searching for insects and spiders? Well, despite some common beliefs, arthropods (members of the phylum Arthropoda – insects, spiders, crustaceans...) represent an endlessly varied, wildly beautiful and fascinating bunch of animals with surprisingly personable faces and behavior. Often, all it takes is simply inspecting their lives on a closer level to turn repulsion to reverence”. – Thomas Shahan

Photo: Adult Male Jumping Spider at Sunset – Phidippus mystaceus. (Photo by Thomas Shahan; Source: Flickr)

A large bull walrus returns to the shores of Prins Karl Forland after diving and feeding on clams. (Photo by Paul Nicklen/National Geographic). Svalbard, Norway, 2011

Vivid colors and bizarre shapes come together in a false-color image that could be an illustration for a fantasy story. This labyrinth of exotic features winds its way along the edge of Russia’s Chaunskaya Bay in northeastern Siberia, seen as a vivid blue half-circle at the bottom of the image Two major rivers, the Chaun and Palyavaam, flow into the bay, which in turn opens into the Arctic Ocean. Ribbon lakes and bogs are present throughout the area, created by depressions left by receding glaciers. (Photo by USGS/NASA)

The sea leopard. The Antarctic Peninsula. (Photo by Paul Nicklen)

A leopard seal feeds Paul Nicklen a penguin. (Photo by Paul Nicklen/National Geographic). Antarctic Peninsula, 2011

Brad Snead walks past melting ice on the Cook Inlet beach, Saturday, March 26, 2011, in Kenai, Alaska, while looking for agates. (AP Photo/Peninsula Clarion, M. Scott Moon)