The U. S. Army Ordnance Museum, at Aberdeen Proving Ground, Maryland is Harford County's largest tourist attraction with roughly 250,000 visitors each year. The museum's world-class collection of arms, armor and technology, possibly the largest in America, depicts the evolution of America's military and technological developments alongside those of foreign nations. Several exhibits are the last of their kind in the U. S. if not the world. The museum collection is a reminder of the sacrifices made by our ancestors to insure the freedoms we enjoy today.