Raysko Praskalo is the highest waterfall in Bulgaria located north east of Karlovo, just under the mountainpeak Botev (2.376 m).
There are several trails going to the waterfall Raysko Praskalo, which also can be written as Raisko Praskolo or in Bulgarian: Райско пръскало. I think the best point to start is from the north side of the village Kalofer (which also has a train station) at Panitzite (Kalofer Bungalows). There the trail starts (gps 42.660467, 24.978871) to Raysko Praskalo. I am not sure if it is a problem to park the car at the park.
From the trailhead it is a 9 km walk with a descend of appr 700 meter. The hike should take 4 hours (one way).
Raysko Praskalo literally means “heavenly spray”. Melting water form the mountain Botev jumps over a cliff and ends, in a single drop, 125 meter down. In springtime (or in autumn) the water flow is on its maximum. In summertime the waterfall is less impressive.