The largest and most destructive fire burning in California continues to grow, consuming dry brush as it races not just through but across the canyons north of Los Angeles. Strong winds and dry conditions mean flames can leap large distances, prompting thousands to evacuate their homes. The Thomas Fire has now spread from Ventura County into Santa Barbara County, burning up 230,000 acres—an area larger than New York City and Boston combined. The out of control blaze is on track to become one of the largest in California history.

So firefighters are using the largest tools they have to tackle it, including one that's more than 200 feet long, and does its work from just 200 feet above the ground.

“We avoid flying through smoke at all costs, but you can smell the fire 200 miles out, even at 20,000 feet,” says Marcos Valdez, one of the pilots of the Global Supertanker, a Boeing 747 modified to fight the fiercest of fires. The jumbo jet can drop 19,200 gallons of fire retardant liquid per trip, nearly double the capacity of the next largest air tanker, a McDonnell Douglas DC-10. Fully stocked, the plane weighs in at 660,000 pounds, comfortably under its 870,000-pound max takeoff weight.

Step inside (which you can do in the interactive 3-D model below) and you'll see that the upper floor looks pretty normal, with the cockpit and a few seats. Head down the stairs to the main floor, though, and you'll see the key changes its owner, Global Supertanker LLC, made when it converted the Japan Airlines passenger plane to a firefighter in 2016: In what looks like the interior of a submarine, you'll find eight cylindrical white tanks in two rows.

Holding the fire suppressant liquid in separate tanks means the 747, aka The Spirit of John Muir, can make up to eight segmented drops on multiple small fires, or put down a solid two miles of fire line, to try to protect property or contain a fire. The liquid drops through a big hose, through a series of manhole-cover-sized circular nozzles under the plane, near the back. (If you use the "Dollhouse" view on the 3-D model, you can see some of that detail on the very lower deck.)

The plane is based in Colorado Springs, but its owner contracts it out to fire agencies in need. This week it's flying out of Sacramento, in the northern part of the state. That's because it can carry so much flame retardant that picking it up in Southern California wouldn't leave enough for the smaller aerial firefighters. Plus, with a 600-mph cruise speed, it can reach the perimeter of the Thomas fire in just 38 minutes.