Ever since the first tourists discovered the Vitosha as the fastest way to leave the pollution and chaos of the big city and roam among pristine nature, the moreni, or moraines – massive boulders that cascade amid the firs, a hidden river rumbling beneath them – have been top of the must-see list.

The moreni are easy to visit, safe to explore and fascinate year round. Though the rivers of stone they form are scattered through the Vitosha, the Golden Bridges, just a few miles away from the Boyana neighbourhood of Sofia, is one of the favourite spots. A number of paths start from the Golden Bridges. If you follow them you can take an easy walk to Vladaya village, a more challenging trek to Boyana Waterfall or a longish journey all the way up to Vitosha's summit, Cherni Vrah. Huts and restaurants abound near the Golden Bridges, yet another reason for the moreni enduring popularity among Sofianites who seek some respite from the stress of the ever growing capital.

But what are the Golden Bridges?

Just like the name of Cherni Vrah, or Black Peak, reflects its dangerous nature – sunlight can give way to a sudden hailstorm even in summer – the Golden Bridges are named after their outstanding qualities. Sometimes, in the right light, the lichens that cover the boulders can glitter as gilt. Despite their massive size, the boulders provide a relatively easy climb, a true natural bridge.

Interestingly, the moreni, though called that, are not exactly moraines. The latter are the rock debris of various shapes and sizes created when glaciers melted down steep mountain slopes and dislodged boulders on their way. They remain in place long after the glaciers are gone. In its geological history the Vitosha never had glaciers. With the driving force behind moraine formation missing, scientists have come up with another explanation of how the Golden Bridges appeared.

The boulders of volcanic rock were carved through the millennia by the combined force of running water and erosion. They form the so-called rock river. The water that still can be heard running underneath them is their actual creator.

You can go to the Golden Bridges either by car from Boyana (the road is closed for private vehicles between 10 am and 3 pm on weekends) or by buses 61 (first stop at the Lovers' Bridge by NDK) and 63 (first stop on King Boris III Blvd close to the intersection with Ivan Geshov Blvd).