Glezos is best remembered for his heroic act, together with Lakis Santas in 1941, of climbing Athens’ Acropolis Hill at night and taking down the Nazi swastika flag flying there early the next morning, dealing a powerful symbolic blow to the powerful occupying forces.
Santas, a 19-year-old law student at
Athens University, and Glezos, his 18-year-old friend,
determined to remove the Nazi flag which, as they put it, "offended all
human ideals". They discovered, from a library book, that the north side
of the Acropolis contained a natural cave leading from the base to the
top which had been used as a secret passage in ancient times and seemed
to offer a chance of evading detection.