At about 1.5 km from the Kaltene seaside, the coastal forest hides large boulder piles called kalvas.Nature scientists believe that those wall-like piles of boulders, now overgrown with forest, were formed several thousands of years ago by the receding Baltic Glacial Lake. However, a local fisherman you meet on the beach has a different story to tell: "In the days of yore, the Devil was carrying rocks from Sweden to Talsi, to build the tenth hill. He was too slow and did not manage to finish his job while still dark. At dawn, when a Kaltene rooster crowed, the devil dropped the pile of rocks and fled."
It remains up to the traveller, which version to believe. The kalvas of Kaltene is a national-scale protected natural monument, and in 2006 special trails were laid out for viewing those unique formations. Travellers can choose between a shorter or a longer walk: the shortest loop trail stretches for about 800 m, but the longest – for 1.5 km. The tallest kalva, called the Devil's Kalva, once rose as high as treetops, but was fully demolished in 1960-70s in order to obtain stone chips for road building. Only a small lower part of the kalva, 300 m in length and 2 m high, has survived. The Kārdūži Kalva, for its part, has been preserved intact: it is a 1 km long, 50 m wide, and 1.5 m – 2.5 m high, slightly winding ridge of boulders. People believe that in the ancient times kalvas were sacred sites, and thus a number of tales and legends about them are still alive these days.
When walking along the 800 m long Kaltene Nature Trail, you will find out many interesting things about the birds which are native to Latvia, and about the migrating species. The trail includes two viewing platforms and a tower for watching birds all year round. The best season for visiting the Kaltene Nature Trail is spring and late summer, but it is worth doing this also in winter, unless the sea has been frozen over. The platforms and the tower offer 'guide posters', which allows beginner bird watchers to identify birds and enjoy this unique site. The route takes about half a day to cover.