Places to visit outside Prague
Terezin Concentration Camp and Memorial
Incredibly moving place to visit just to the north of Prague.
http://www.pamatnik-terezin.cz/en?lang=en
Bohemian Switzerland
The territory of the Bohemian Switzerland National Park – the youngest of the Czech Republic’s four national parks – forms a part of the larger territory of the Elbe Sandstones, which has been called Czech and Saxon Switzerland for nearly two centuries.
http://www.ceskesvycarsko.cz/en/bohemian-switzerland-national-park
Ceský Krumlov
Historic city set in beautiful countryside with lots of fun activities to do including water activities.
http://www.ckrumlov.info/docs/en/kaktualita.xml
https://www.lonelyplanet.com/czech-republic/bohemia/cesky-krumlov
Lipno
http://www.stezkakorunamistromu.cz/en/
http://www.lipno.info/en/adventures.html
Karlštejn Castle and Town
Beautiful medieval castle and town set in some amazing countryside only a short train ride from Prague. Tours in English available.
Great hiking nearby to incorporate a trip to the castle.
https://www.hradkarlstejn.cz/en
https://en.wikipedia.org/wiki/Karl%C5%A1tejn
Kutna Hora
A historic city with some interesting buildings and beautiful views. Also there is the Sedlec Ossuary which is estimated to contain the skeletons of between 40,000 and 70,000 people, whose bones have, in many cases, been artistically arranged to form decorations and furnishings for the chapel.