Kola Superdeep Borehole

A journey to center of the earth is nearly come true. The Russian already make the deepest borehole that man can made, until now. The Kola Superdeep Borehole (Russian: Кольская сверхглубокая скважина) (Transliteration: Kolskaya sverkhglubokaya skvazhina) is the result of a scientific drilling project of the Soviet Union on the Kola Peninsula. The project attempted to drill as deep as possible into the Earth's crust.

Drilling began on 24 May 1970 using the Uralmash-4E, and later the Uralmash-15000 series drilling rig. A number of boreholes were drilled by branching from a central hole. The deepest, SG-3, reached 12,262 metres (40,230 ft) in 1989, and is the deepest hole ever drilled, and the deepest artificial point on Earth. For two decades it was also the world's longest borehole, in terms of measured depth along the well bore, until surpassed in 2008 by 12,289 m (40,318 ft) long Al Shaheen oil well in Qatar, and in 2011 by 12,345 metres (40,502 ft) long Sakhalin-I Odoptu OP-11 Well (offshore the Russian island Sakhalin). However, in terms of depth below the surface, the Kola Superdeep Borehole still retains the world record as of 2012.
Unfortunately, the project was closed down in late 2005 due to lack of funding. All the drilling and research equipment was scrapped and the site has been abandoned since 2008.  The deep core-drilled Kola borehole cannot be directly compared with any other borehole in the world. In a deep core borehole, a section of the rock drilled through is recovered from within the hole. It is this recovered drill core, and the information it represents about the rock that it was retrieved from, that is the most important feature of the borehole.
The Kola borehole penetrated about a third of the way through the Baltic continental crust, estimated to be around 35 kilometres (22 miles) deep, reaching rocks of Archaean age (greater than 2.5 billion years old) at the bottom. The project has been a site of extensive geophysical studies. The stated areas of study were the deep structure of the Baltic Shield; seismicdiscontinuities and the thermal regime in the Earth's crust; the physical and chemical composition of the deep crust and the transition from upper to lower crust; lithospheric geophysics; and to create and develop technologies for deep geophysical study.
To scientists, one of the more fascinating findings to emerge from this well is that the change in seismic velocities was not found at a boundary marking Harold Jeffreys's hypothetical transition from granite to basalt; it was at the bottom of a layer of metamorphic rock that extended from about 5 to 10 kilometers beneath the surface. The rock there had been thoroughly fractured and was saturated with water, which was surprising. This water, unlike surface water, must have come from deep-crust minerals and had been unable to reach the surface because of a layer of impermeable rock.
Another unexpected discovery was the large quantity of hydrogen gas, with the mud flowing out of the hole described as "boiling" with hydrogen.

Do you interested to continue the borehole? :)

source: Wikipedia.com