It's interesting to look into differing beliefs and values. An outing to Rotunda of John the Baptist is an excellent way to experience a part of the local culture.
If you're staying a while in Koper, Rotunda of John the Baptist is a good place to kick off your exploring. This house of prayer is one of many attractions that'll keep you on the go here. Izola Marina, Lighthouse Park, and Nereo Rocco Stadium are also ready to be explored nearby.