You can see how flat and open and boggy it is. The highland army was completely exposed, and they then charged into the teeth of musket fire, cannons, mortars… with nothing more than their broadswords, for the most part. It was very, very quick and very bloody. The whole thing took less than an hour. How many were killed? Jacobites lost something in the region of 2000 men. 

But the interesting thing is that in the years following Culloden, the estates of the Clan Chieftains were plundered, sold. The government banned the wearing of the tartan. They banned the carrying of swords, even the Gaelic language. In effect, Culloden marked the end of the clans. The end of the highlander way of life.