Down the Barrel of a Canon

At the Rijksmuseum in Amsterdam, this is the canon of the Amsterdam Admiralty and was made in 1615. Made of bronze, copper, tin, lead and iron it could fire 18 lb canon balls. To absorb the recoil, the gun was mounted on a wheeled carriage and took 8 men to operate. 

My extra is a blip of the Library (clock the spiral staircase). The website tells that its the best and largest public art history research library in The Netherlands. 

So many other choices of photos - a glorious art collection.