HERA (Hadron Elektron Ring Anlage) was a 6.3-kilometer-cirumference proton-electron collider at DESY, Hamburg, Germany.

The storage ring started in 1992 and joined the effort of 11 countries.

HERA had four huge detectors and associated experiments H1, ZEUS, HERMES and HERA-B.

The experiments were dismantled in 2007

HERA-B detector stopped taking data in 2003.