Any wi-fi, Europe or USA has the insecurity of being "sniffed" by anyone within range. They could be in a hotel room a few floors away across the street or sitting next to you. This has been known for a number of years.
As one poster said. Don't do anything on wi-fi that uses sensitive passwords that you wouldn't want stolen. Don't make online purchases, log in to any financial accounts, etc. That's it!
But what if your DO need to log in to those things?
Then as another poster said, you can use a cellular connection which is much more encrypted and secure than wi-fi, but slower and more expensive.
But what if you DO need to log in to those things using wi-fi?
There are cheap solutions.
On our last trip, my wife and I used hotspotshield.
It's an inexpensive app you activate just after you connect to the wi-fi hotspot but BEFORE you log in to the sensitive account. It's known as a VPN or "tunnel" in the trade. It worked well for us.
Another company, vipervpn has more egress points internationally and a few extra features.