During the Battle of Antietam, McClellan’s left wing, commanded by General Ambrose Burnside, had a tough time getting across Antietam Creek. In particular, they found it difficult to rush successfully the Lower Bridge, and were held up for several hours by a minimal Confederate force on the heights overhead. But, did they need the bridge to cross the creek? Well:

I think the answer is pretty clear, if slightly damp.
(In response to reaxx’s question. Photo by Elisabeth K. Boas).

