Located where the Sava takes on the task of tracing Croatia's long east–west border with Bosnia and Herzegovina until taking a turn into Serbia more than 150 km (94 miles) away, Jasenovac is the site of Croatia's most notorious World War II labor camps. Current estimates are that somewhere between 56,000 and 97,000 people—mostly Serbs, it is believed, along with Jews, Gypsies, and Croatian antifascists—perished at this string of five camps on the banks of the Sava River between 1941 and 1945 from exhaustion, illness, cold weather, and murder.
As a contrast to the labor-camp memorial, Jasenovac is also home to the headquarters of the beautiful Lonjsko Polje Nature Park. One of the largest floodplains in the Danubian basin, this unique ecological and cultural landscape of 20,506 acres along the Sava River was accorded park status in 1990 and is included on UNESCO's roster of World Heritage sites. It has numerous rare and endangered plant and animal species, from white-tailed eagles and saker falcons to otters and the Danube salmon—as well as storks, which are as easy to come by as in Čigoć. Its 4,858 acres of pastureland is also home to Croatia's highest concentration of indigenous breeds of livestock. Traditional village architecture—in particular, houses made of posavina oak—further contributes to the region's appeal. The park office provides park maps and other information on where to go and what to see; and, yes, it issues park entrance passes (40 Kn). The easiest way to access the park is by car: while driving from Zagreb, exit the motorway at Popovača and take the road to the right through the villages of Potok and Stružec toward Sisak.