Town of Health and Spartakus
I've been only once to Sandanski- took a train in the morning from Sofia, hung out all day and then got on the night train back to. It's 173 km SW from Sofia, and 22 km from Kulata (the cross-border checkpoint with Greece).
We hung out in the park, by the pool.....btw Sandanski is the place to go if you have health issues. The mineral springs here are reported to treat dozens of diseases (respiratory, kidney, nervous and so on). Pretty much if you're sick with something, doctors in Bulgaria send you to a "balneosanatarium" aka spa resort such is Sandanski.
The climate is unique here they say... it was april and we're sweatening from heat -the temperature is highest than the average for Bulgaria due to its southern location.
It's supposed to be the place in Bulgaria with the least rain, but in the end of our day trip it was pouring cats and dogs !?!?!
Around Sandanski there bunch of trails for hiking in the Pirin mountain. I think the best time to go would be in the spring, before it gets too hot and dry.
Did you know that, Spartakus, the slave/ leader of the biggest riot of the Roman was born here; you know that movie with Kirk Douglas directed by Stanley Kubrick?