How to observe
Are you interrested in (virtual) air traffic control? Do you want to know how does this work? If yes, download package from this page. After successfull installation and configuration you'll see air traffic over Czech Republic.
You might know some older ATC clients like VRC or ASRC. Although they are still formally supported, all VACC-CZ controllers are now using only the Euroscope (ES) so you'll find here only the ES setup.
Radar screen example