The U.S. Army rolled across the Danube River on Thursday, in a show of force meant to demonstrate the cohesion of the western alliance and the capability of the American Army to move across Europe quickly.

Forty-one armored Stryker vehicles and 500 soldiers from the 2nd Cavalry Regiment, known as the Dragoons, began crossing the Danube River on a Hungarian pontoon bridge Thursday morning in Gyor, Hungary. Over 96 hours, the regiment’s reconnaissance squadron has been making a very public road march through Germany, the Czech...