Near to Presov in locality of Dubnik is forgotten mine. It's one of two places where opal(hyalite) was found. The other one is in Australia. You can find the biggest opal of the world in Naturhistorisches Museum in Vienna. It was found in Dubnik. There are guided tours, DON'T MISS IT. From 1st of April till 30th of September(09:00 to 17:00). Reservation 2 days before. You will get to past when to mine was hard work...
there are mineral springs...
there are mineral springs around presov. you can take a nice walk through the woods to cemjata or borkut, refresh yourself at the spring and even bring home some water if you take a bottle with you. i like these walks during spring. the pathes are well marked