One way to preserve Alcatraz? Capture everything in 3D.

In May 1946, chaos broke out when six prisoners, determined to escape from Alcatraz Island, overpowered the guards and took weapons and keys.

They seized a cell block of the federal prison for two days, prompting the Marines to respond and throw grenades into the building from the roof. By the end of the “Battle of Alcatraz,” in the middle of San Francisco Bay, three prisoners and two guards were dead.

Seventy-eight years later, tourists at the prison-turned-park can still see the pockmarks in the cement floor left by the hurled explosives.

The divots, shallow in size but deep in history, will now be preserved forever, along with every other corner on Alcatraz. Scientists and technology experts spent three weeks in December using cameras, drones and a robotic dog to collect four trillion bytes of data to build the first full-color 3D map of the entire island.

Every building, inside and out, was frozen in time. Every tunnel, every patch of cellblock graffiti, every rusted prison bar, every wildflower, every seagull falling. Every corner of “the Rock” was captured with precision within an inch.

The unusual project grew out of concerns about climate change and sea level rise that will inevitably encroach on Alcatraz, where parts of the perimeter wall are already eroding and falling into the bay. Scientists have warned that California could experience several feet of sea level rise by the end of the century, along with increasingly dangerous storm surges.

The 3D map could help local leaders monitor the effects of climate change on the San Francisco Bay Area. It could also allow National Park Service officials to visualize potential flooding at Alcatraz and protect the island from future damage, said Pete Kelsey, a technologist who led the mapping project.

For example, he noted that the wharf would be in serious danger if the water rose, and the boats moored there not only bring tourists, but also bring in fresh water and discharge sewage. Without a dock, the island would quickly become unusable, he said.

Because Alcatraz is so well known around the world, the map “could be a vehicle to wake people up, to bring people into a different kind of consciousness about climate change,” Kelsey, 62, said.

Alcatraz, just over a mile north of San Francisco, has had many chapters. It was originally a fortress and military prison. During its most famous period, from 1934 to 1963, it functioned as a maximum-security federal prison and housed such infamous convicts as Al Capone, Machine Gun Kelly and Robert Stroud, known as the Birdman of Alcatraz.

In 1969, Indians occupied the area for nineteen months in protest against the government’s treatment of their people. After opening to the public in 1973, Alcatraz has become a popular tourist attraction and bird sanctuary that is part of the Golden Gate National Recreation Area.

Like many National Park Service properties, Alcatraz is at risk on many fronts. It is facing a possible earthquake. It is vulnerable to fire or flooding. It could be the target of a terrorist attack. It is also suffering from the wear and tear of 1.5 million visitors a year, with some buildings and equipment seriously deteriorating.

Strolling around the island recently, Mr. Kelsey said it was important to have a 3D baseline to monitor changes and damage to Alcatraz. Mr. Kelsey owns Seattle-based VCTO Labs, which has captured everything from military ships to football stadiums for the purposes of preservation, education and filmmaking.

“The data we capture can answer questions,” he said. “It can lead to discovery. It makes the invisible visible.”

The National Park Service retains the rights to the 3D map and no money was exchanged to create the map, Mr. Kelsey said.

He believes the 3D map offers the National Park Service endless possibilities. It could be used by movie studios, who would not need to film on Alcatraz but could instead use the 3D data with a green screen. It can be turned into a video game or a virtual reality experience using Apple Vision Pro or Meta headsets. It could be replicated with a 3D printer.

“My selfish dream is for this to be the world’s first virtual national park,” Mr Kelsey said.

Pete Gavette, a park archaeologist, said there had been smaller attempts to map the island before, but this was the first time “every nook and cranny” had been mapped in 3D. Mr Gavette said it would be helpful for park staff to be able to see every corner of the island, as staff members are not allowed to enter areas deemed too dangerous due to asbestos, lead paint or structural damage.

For example, he noted that the apartments where the families of prison guards once lived are inaccessible because entire stairs and parts of floors are missing.

The 3D map is almost complete, but Mr Gavette said creating a virtual reality tour of the island would take some time.

Obtaining permission for the project – specifically the right to fly drones, which is not normally allowed in national parks – took nine months. Then Mr. Kelsey had to wait until the breeding season was over to avoid disturbing the bird colony on the island.

To collect the data, he recruited 26 scientists and technology specialists from around the world to work for free. Some, including Mr Kelsey, lived on the island for three weeks in December, bringing all their food with them, not showering and sleeping in prison cells. They were given a golden key that unlocked every door on the island.

They flew drones into hard-to-reach holes, such as in the top of the chimney, where they had to protect the aerial devices with cages to protect against any damage that might have been caused by crashing into the walls. They sent a robot dog to other places where it was not safe for humans to enter.

They mapped out the powerhouse and its “Alcatraz steampunk” vibe, as Mr. Gavette described it. They mapped the underground citadel and the dungeons where military prisoners were held. They mapped out the prison hospital, where prisoners believed to be mentally ill were locked in small rooms, where their trays of food were passed through narrow slots in the wall.

Mr Kelsey said the mapping had given him insight into the horrific treatment of some of the people imprisoned there and that he still sometimes hears screams in his head.

He has mapped other locations around the world, including Easter Island and Africatown, an Alabama community founded by former slaves. At the end of each project he always gets a tattoo.

Soon, he said, he’ll get a new one: the key to Alcatraz.