Long Lines by the Hungarian Parliament on August 20
On August 20 the Hungarian Parliament is open, and as it is a national holiday it is free to visit for all. However, the queue that builds up on Aug 20, which is usually a hot day in Budapest, Hungary, is so long that only the very patient are encouraged to join the thousands of Hungarians who wish to get into the Parliament on this day.
Hungarian Parliament tours can be pre-arranged, but not for national holidays. Try to schedule your visit for Aug 19 or Aug 21 instead.
Here is a short video showing the usual long lines queuing for getting into the Parliament in Budapest on Aug 20.