The Euros are getting into a swing now. Thankfully the medical drama of Saturday has turned out better than feared. Get well soon Christian Eriksen.
The two Central European nations get their tournament up and running in St Petersburg.
Poland

My favourite city visited in Poland is the Hanseatic port city of Gdańsk.
Lovely old town buildings in the Dutch style, colourful, narrow & gabled.
The best activity though is to wander the historic shipyards, the home of Lech Walesa and the Solidarity Union who were instrumental in returning Poland to democracy and starting the revolution ball rolling in knocking down decades of Communist rule.

Slovakia

I first visited the Slovak capital in 2016 on a 36-hour solo trip.
Forever in Prague’s shadow when Czechoslovakia existed as a nation, Bratislava is nevertheless a fine city in its own right.
Situated on the Danube, the climb up to the castle is well worth it for some great views of the old town and the banks of the great river.

Score prediction – Poland 2 Slovakia 1
Gdansk is high on my to do list. I went to Bratislava in 2009.
Wroclaw is on mine after reading your articles.