The California Army National Guard armory in Kearny Mesa kept its M60A3 tanks behind a padlock. On the afternoon of May 17, 1995, the armory gates were unlocked — and Shawn Nelson simply walked in.

Nelson was familiar with military equipment. He was a former Army veteran and plumber who had grown up in San Diego. In the years leading up to that afternoon, he had accumulated a long list of setbacks: lost jobs, a failed plumbing business, a house he'd been trying to dig out from under — allegedly by digging for gold in his own yard, a fixation that alarmed his neighbors. He had struggled with substance abuse for years. By May 17, 1995, he was, by all available accounts, a man who had run out of reasons to stay within ordinary bounds.

He broke off the padlock securing the tank, climbed inside, started the engine, and drove through the armory wall.

An M60A3 weighs 57 tons. It is designed to survive artillery fire. Parked cars are not artillery.

Nelson drove the tank through the residential streets near the armory for about six miles, then onto State Route 163 before the tank's treads — which are designed for open terrain, not asphalt — tore up the road surface and the vehicle eventually became stuck on the highway median. Cars were crushed flat. Fire hydrants were knocked aside. A section of concrete freeway divider crumpled. The tank's passage was visible from miles away.

For 25 minutes, San Diego police chased the tank in vehicles that could not stop it and used radios to coordinate with anyone who might be able to help. Helicopters tracked it from above. Bystanders pulled out cameras. The scene was surreal in a way that didn't entirely register until afterward: a military tank, stolen, driving through a city, and there was nothing obviously to be done about it.

When the tank's left tread was torn apart on the freeway median and the vehicle stopped moving, police moved in. Officers climbed onto the hull and forced the hatch open. Nelson was inside, alive, and reportedly attempting to free the tank from the median.

Officers shot him. He died at the scene. His blood alcohol content was twice the legal driving limit.

The district attorney reviewed the shooting and determined it was justified. Critics argued that police had not tried to negotiate with Nelson, or to incapacitate him with tear gas rather than lethal force. Whether other approaches were feasible in those 25 minutes — with a stolen tank moving through a city and a driver whose mental state was unknown — became part of the debate that followed.

The National Guard was held financially responsible for the property damage Nelson caused — the crushed cars, the torn-up road, the broken infrastructure. The incident prompted a review of security practices at armories across California, and changes were made to how tanks were stored and secured.

For a few days in May 1995, the San Diego tank rampage was national news — a story so strange it felt impossible, then felt inevitable once you heard the details. A man who had lost everything. An unlocked gate. A tank that no one had thought to secure against something like this because something like this had never happened before.

Shawn Nelson's motives remain unknown. He died before anyone could ask him. The tank itself was eventually displayed in a museum, a 57-ton artifact of an afternoon when San Diego learned something unexpected about the gap between security and the appearance of it.