W-hour - 17:00, August 1st, 1944, the moment when the Warsaw Uprising started.
At 5PM all transportation stopped to give a tribute to the uprisers. For one minute cars, buses, tramways were blowing horns, the sound sirens and church bells in whole Warsaw were ringing, people were standing at attention.

The Warsaw Uprising was a World War II struggle by the Polish Home Army (Armia Krajowa) to liberate Warsaw from German occupation. The Uprising began on August 1, 1944 and continued for 63 days (until October 2).
Polish losses amounted to 18,000 soldiers killed and 25,000 wounded, in addition to between 120,000 and 200,000 civilian deaths, mostly from mass murders conducted by retreating German troops.
German casualties totalled over 17,000 soldiers killed and over 9,000 wounded. During the urban combat approximately 25% of Warsaw's buildings were destroyed.
http://en.wikipedia.org/wiki/Warsaw_Uprising

August challenge, more to see http://forum.pbase.com/viewtopic.php?f=16&t=41842&sid