A stroke of a pen cut this town in two. In 1920, the Treaty of Trianon turned the Danube into a border, leaving the historic centre on the Slovak side and the southern suburbs on the Hungarian side. Those suburbs became Komárom, a Hungarian town in its own right, where ships sailing the river between Vienna and Budapest dock. The port call surprises with its main attraction: one of the largest 19th-century fortified complexes in Central Europe, long closed to the public and now wide open to curious walkers. Add thermal baths and a bridge that spans a border, and the day fills itself, all within a few kilometres of the landing.

Fort Monostor, the Underground City

Built between 1850 and 1871 on the heights overlooking the Danube, the fort covers about seventy hectares of bastions, courtyards and galleries partly buried beneath grassy mounds, so that from the river you can barely make anything out. You wander among brick barracks, powder magazines and vaulted corridors that stay cool even in midsummer, with a smell of stone and saltpetre worthy of any film set. In places, arrow slits cut the light into thin blades, and the silence of the galleries makes groups lower their voices without thinking. Exhibitions set up in the casemates trace garrison life, period artillery and the site's eventful history, used as a military depot until the Cold War. River cruise line excursions cover the highlights with a guide; independent explorers can spend half a day here without running out of corridors.

A Complete Defensive System

Monostor was only one piece of the system. Igmánd to the south and Csillag to the east, together with the great citadel on the opposite bank, formed a lock capable of controlling all Danube traffic. Walking along the bank, you grasp the logic of the place: here, the Habsburg Empire guarded one of its strategic gateways, and nothing passed without being seen. The russet brick ramparts, softened by grass and linden trees, now serve as a promenade for neighbourhood families, and children cycle down the glacis where regiments once drilled. Bilingual signs help you find your way, and the wardens are happy to point out the corners not to be missed.

The Baths, a Walker's Reward

Like so many Hungarian towns, Komárom has its thermal baths, fed by hot water that rises from the ground a few hundred metres from the river. Indoor and outdoor pools, massage jets and shaded lawns make for an unpretentious setting, frequented mainly by locals, towel under one arm and newspaper in the other hand. After kilometres of military galleries, an hour in the warm water restores tired legs and offers a very real glimpse of the Hungarian art of living, passed down from generation to generation in the steam of the pools. You come out relaxed, your mind still full of vaulted corridors, ready to see the river in a new light.

Landmarks on the Hungarian Bank

In the evening, as the boat pulls away from the dock, the green mounds of Monostor blend into the hills and you can barely guess what they conceal. Komárom unfolds like an open-air history lesson: a river turned border, a stronghold turned promenade, and two twin towns that continue, each on its own bank, the same long conversation.