The European Technical Center (ETC) is a U.S. National Security Agency (NSA) signals intelligence facility in Mainz-Kastel, Wiesbaden, Germany.
Located in Building 4009 of the U.S. Army's Mainz-Kastel Storage Station, the facility serves as the NSA's "primary communications hub" in Europe.
[1] In December 2005, a metal object discovered near the facility was suspected of being an undetonated World War II explosive.
On January 24, 2006, NSA analysts evacuated the ETC while the object was investigated, shutting down the center for a full day.
[1] In 2010, the center began experiencing technical difficulties, losing power over 150 times over the period of a few months.