There is absolutely no better way to explore a place that in company of a person that actually lives there. You will be able to walk around the “unknown” parts of the cities, go to the best pubs and restaurants, learn some new words in the local language, and learn about the culture and the history, and the best part, you get to know new people. You can find friends anywhere, I have learn along the way that all people is nice, you can find friends in the plain, in the bus, in the pub, etc. But don’t worry, if you are a bit shy to talk to strangers in a bar, there are also some apps that can help you hang around with locals and make the best out of your trip.
Couchsurfing. This app is not only handy to find places to stay for a couple nigths, it also has a feature to find people to hang out with, you are just a click away from knowing your next friend!
Download the app here: https://www.couchsurfing.com/