Most travelers have heard of the Wachau region. The fertile hillsides along the Danube River have long been designated as a World Heritage region for its cultural and natural landscapes. But just across the river is another slice of forest, the Dunkelsteinerwald, that’s not quite as famous but just as beautiful. On a mid-October weekend, we hiked from the pilgrimage town of Maria Langegg up the restored Aggstein Castle, which was built in the 12th century. Like many others along the Danube, the castle was an outpost for charging toll to passing ships, a payment made in exchange for maintaining the paths along the shore that were used to tow ships upstream. But the area was inhabited long before that, with signs of civilization dating back to the Celtic era — and long before. Just across the river, construction workers in 1908 unearthed the famed Venus of Willendorf, a prehistoric fertility figurine dating back to about 25,000 BC.