It's hard not to be mesmerized by the detail in Altdorfer's Battle of Alexander at Issus [I've already mentioned another of Alexander's conquests]
If you prefer sea-battles to land, then you can go with Vicentino's Battle of Lepanto.
Tetar van Elven helpfully assembled this Imaginary View of the Main Monuments of Italy
This is only about half of Isabella of Parma's wedding. [Though I am glad I searched for (school of) van Meytens, because then I found this and this.]
These fish are strangely charming
There was a time when you were nobody if you didn't have a crocodile hot-glued to your ceiling.
One of these shelves doesn't belong.
Because I am an ignorant American, I had no idea one of the important events at the outset of the French Revolution happened in a tennis court.
I like Callot's Temptation of St. Anthony, since the temptation part is in a postage-stamp sized part of the canvas, while a giant flaming dragon-Satan looms over everything. I can't find the luridly colored painting, but this engraving gives you an idea.
They just don't make movies like this anymore.