  The Extreme Energy Events (EEE) experiment, dedicated to the study of
secondary cosmic rays, is arguably the largest detector system in the world
implemented by Multigap Resistive Plate Chambers. The EEE network consists of
60 telescopes distributed over all the Italian territory; each telescope is
made of three MRPCs and allows to reconstruct the trajectory of cosmic muons
with high efficiency and optimal angular resolution. A distinctive feature of
the EEE network is that almost all telescopes are housed in High Schools and
managed by groups of students and teachers, who previously took care of their
construction at CERN. This peculiarity is a big plus for the experiment, which
combines the scientific relevance of its objectives with effective outreach
activities. The unconventional location of the detectors, mainly in standard
classrooms of school buildings, with heterogeneous maintenance conditions and
without controlled temperature and dedicated power lines, is a unique test
field to verify the robustness, the low aging characteristics and the
long-lasting performance of MRPC technology for particle monitoring and timing.
Finally, it is reported how the spatial resolution, efficiency, tracking
capability and stability of these chambers behave in time.
