'Continental deep-drilling program of the Federal Republic of Germany'), abbreviated as the KTB borehole, was a scientific drilling project carried out from 1987 to 1995 near Windischeschenbach, Bavaria.

After the drilling project ended, the German Research Centre for Geosciences used the borehole to install a seismic deep observatory (Tiefenobservatorium) which was active from 1996 to 2001.

In October 1986 the German Minister for Research and Technology (Bundesminister für Forschung und Technologie), H. Riesenhuber, officially announced that the super-deep borehole of the Continental Deep Drilling Program of the Federal Republic of Germany (KTB) would be drilled in the Upper Palatinate area of Northern Bavaria.

Immediately following the conference and evaluation of scientific and technical models and targets, members of the DFG Senate Commission for Geoscientific Interdisciplinary Research voted almost unanimously for the Oberpfalz site.

The pilot hole (KTB Vorbohrung, KTB-VB) was spudded on September 22, 1987, and was finished on April 4, 1989, having reached 4,000 m (13,000 feet).

At the Upper Palatinate location, however, it was hoped to reach the Erbendorfkörper – a deep-lying mass that is believed to be on the boundary of a former continental plate and is identified by its characteristic reflection of seismic waves.

Other theory changes were also required – it had been expected that the large tectonic pressures and high temperatures would create metamorphic rock.

Due to the heat and fluids, the rock was of a dynamic nature which changed how the next super-deep drilling needed to be planned.

[3] These experiences were the foundation of the follow-up project, the International Continental Scientific Drilling Program (ICDP) founded in 1996.