One of Europe’s largest fortresses at the start of the 20th century, the Ring Fortress of Przemyśl is a fine example of Austro-Hungarian defensive architecture. Composed of dozens of individual forts throughout the wooded hills surrounding Przemyśl, today the heritage site comprises a somewhat forgotten monument to World War I. Manned by soldiers from many nations during World War I, many of the forts were deliberately destroyed before being surrendered to the Russians after the Siege of Przemyśł - one of the longest, most deadly battles of WWI, resulting in 100,000 deaths. As a result, today most of the forts that make up the massive fortress system lie abandoned, often embedded in thick undergrowth, in quiet and serene surrounds. An urban explorer's dream, all of the sites are free and accessible to some degree, if you are brave enough to explore the trenches and dimly-lit interiors where history stares you right in the face and the ghosts of the past are never far away, that is. Have protective footwear and a flashlight handy.

If you prefer a less adventurous experience, some of the forts - namely Fort XI Duńkowiczki, Fort VIII 'Łętownia'  and Fort XV 'Borek' - are in better condition, while the Przemyśl Fortress Museum at ul. Katedralna 6 in the centre of Przemyśl will give you an overview of the complex before you head out into the field. All of the main sites along the fortification line are connected by bike paths, so get two wheels under you if you want to visit more than a couple forts; maps of the route can be picked up at the museum, or the Tourist Info Office at Rynek 26.