GALAXIDI, Greece — For a few hours on a single day every year, the prim and elegant Greek seaside town of Galaxidi explodes into frantic childishness.

Riotous groups of residents pelt each other — and unsuspecting visitors — with bags of dyed flour, in a Holi-like end-of-carnival tradition thought to date back to the town's period of maritime glory more than a century ago.

The flour fight, on the coastal road lining Galaxidi's old harbor, takes place on Clean Monday, the beginning of the 40-day Christian Lent fast that ends on Easter Sunday. Although Clean Monday ceremonies abound across Greece, the most common being kite-flying, Galaxidi's flour-fight is unique, and is thought to have been influenced by similar goings-on in Sicily in the 19th century.

Lying about 200 kilometers (120 miles) west of Athens, the town of about 1,700 people was once a major maritime power whose white-masted sailing ships plied a booming trade around the world.

However, Galaxidi ship owners failed to adapt to the advent of steam power in the 19th century, and gradually declined. Its traditional stone houses, the upper floor of which was an open area dedicated to sail-repairs during the winter months, attest to its former glories.

Its economic decline spared Galaxidi from the depredations of modernization that swept the country after World War II, with the town only acquiring a good road link to the rest of central Greece in the 1960s. Until then, it remained a kind of island, nominally attached to the mainland, whose outlook was always to the sea.