With the 2nd Cavalry Group attached, the 90th crossed the Nahe River on March 19th against no opposition, and before nightfall had expanded its bridgehead to a depth of six miles. Once more Task Force Spiess was called upon to exploit the breakthrough.
Divided into three smaller columns Task Force Spiess broke through weak defenses, and by nightfall its leading elements had reached a point only three miles from Mainz itself. Heavy resistance was encountered in the town of Nieder Olm, and the AAF (Army Air Force) was called upon for assistance.
Fighter bombers strafed and bombed, tank destroyers and assault guns moved up to destroy enemy vehicles attempting to escape the town. White flags appeared, but when elements of the Task Force moved in they were met by fire of 20 mm and 88 mm guns. That was deliberate treachery, and American artillery responded sharply. Nieder Olm fell shortly thereafter.