Huge Square in front of the Winter Palace and L'Ermitage Museum. Has a 47,5 m tall Alexandr Column in the middle. It weighs more than 500 tons. Opposite to Winter Palace is Guards Corps Headquarters having nice sculpturer of horses and military men on top if it.
Many significant historical events, e.g. October Revolution and Bloody Sunday took place on this square and even nowadays lot of concerts and events are held here.
You can also ride a horse carriage there :D the carriages look like they are take straight from a fairytale book <3
Not far from Nevsky Prospekt and also leads to Palace Bridge, which is opened at night time ;)