What was the most one-sided battle in history. Sizes of armies, casualties, whatever...

Thermopolae probably.
http://www.hoplites.co.uk/html/thermopylae.html

Still, Operation Mars deserves consideration. I wonder, has there ever been a name to this battle the the Soviet Union wrote out of history?
http://www.battlefield.ru/library/ba...ttle12_04.html

Some other contenders:

The actual invasion of Iraq by Coalition forces during the 1991 Gulf War (qualifies as a single battle) - February 1991. I think you all know about this one!

The Battle of Kiev - August 1941. Probably the greatest disaster suffered by any army in history. 5 entire Soviet Armies encircled and destroyed by the finest modern army in history, the Wehrmacht.

http://www.houseofice.com/history/kiev.shtml

The Battle of Liegnitz - April 9 1241. Europe's finest Knights cut down by the Mongols under the leadership of one of the most brilliant generals in history, Subotai the Valiant.

http://campus.northpark.edu/history/...Europe.CP.html

Barbarossa as a whole was one of the greatest routes ever in history. I'd have to admit that Kiev is a great contender, with the following understanding: "The following battlefield route was brought to you by the stupidest military decision in the history of the modern world."

Good thing Hitler was such an idiot.

That site talking about the battle of Thermopylae was great. I would say that takes the one in my book for greatest odds.

The final battle of New Orleans.

"Finally, on January 8, the day commemorated today as the victory day in the Battle of New Orleans, two British generals, including Major General Pakenham, were killed in battle, with a third severely wounded. Soldiers described battlefield action as confused and haphazard in the dark hours of that foggy morning. Britain suffered over 2,000 casualties in that decisive battle, whereas Jackson lost only 71 men. The British forces withdrew through Lake Borgne and into the Gulf, firing on Fort St. Philip for over a week before sailing out to sea for good."

http://lsm.crt.state.la.us/cabildo/cab6.htm

How about some of them colonial expansion wars in the 17th and 18th centuries?

Originally Posted by godofthunder9010

Barbarossa as a whole was one of the greatest routes ever in history. I'd have to admit that Kiev is a great contender, with the following understanding: "The following battlefield route was brought to you by the stupidest military decision in the history of the modern world."

Good thing Hitler was such an idiot.

You know, some people think Hitler actually made the right decision here. There's a school of thought that says that Armeegruppen Mitte may have been outflanked on their right hand side had they not dealt with the Soviet Armies in the Ukrainian sector first.

I'm not convinced myself I have to add.

Gunny claimed that only 13 Americans died in the battle of New Orleans on Mail call but I find that hard to believe.

Originally Posted by Big_Z

The final battle of New Orleans.

"Finally, on January 8, the day commemorated today as the victory day in the Battle of New Orleans, two British generals, including Major General Pakenham, were killed in battle, with a third severely wounded. Soldiers described battlefield action as confused and haphazard in the dark hours of that foggy morning. Britain suffered over 2,000 casualties in that decisive battle, whereas Jackson lost only 71 men. The British forces withdrew through Lake Borgne and into the Gulf, firing on Fort St. Philip for over a week before sailing out to sea for good."

http://lsm.crt.state.la.us/cabildo/cab6.htm

Decisive?The war was actually over and had been for about a month.

How about Agincourt?French suffered approx 10 to 20,000 killed,the English 500.All that after starting with 40,000 men to the English 5,000.