DEATH VALLEY (AP) — Imagine driving through the desert, passing endless mountains, sagebrush, cactuses and Joshua trees.

Out of nowhere, you spot something huge, opulent, clearly man-made.

We’re talking about Scotty’s Castle.

Originally known as Death Valley Ranch, the property is a 1920s-era mansion located in the northern Grapevine Canyon area of Death Valley National Park, about three hours’ drive from Las Vegas.

Built and financed by Chicago insurance tycoon Albert Mussey Johnson, the “castle” and surrounding buildings and grounds were mostly inhabited by Walter E. Scott, a gold prospector for whom the structure is named.

In addition to the main house where Scott and Johnson lived and frequently entertained guests, the grounds consist of an annex, a guest house, stables, a garage-turned-visitor center, a clock tower and other structures. The entire area is listed on the National Register of Historic Places.

Since the National Park Service purchased Scotty’s Castle in 1970, the grounds have been a major tourist attraction in Death Valley.

Visitors flocked to the area to see the unusually ornate and remarkably intact architecture and furnished interior, and to learn about the unlikely friendship between Johnson, a deeply religious wealthy businessman, and Scott, a heavy drinker and Wild West con man known as “Death Valley Scotty.”

But things changed Oct. 18, 2015, when a historic storm hit Death Valley, dropping 2.7 inches of rain in five hours on a region that typically receives just 3.5 inches (8.9 centimeters) of rain a year. Flooding forced the Park Service to close the campus.

“There hadn’t been a flood anywhere near as large since it had been built,” Abby Wines, Death Valley National Park public information officer and management assistant, told the Las Vegas Sun .

Now, the Park Service is in the process of restoring Scotty’s Castle and making it “flood-proof” so that the desert oasis might last for years to come.

It’s no small project, as the storm caused $52 million in damage parkwide, mostly at Scotty’s Castle.

Officials hope that at least parts of Scotty’s Castle will be ready to reopen by late 2020.

“There’s lots of people who have been coming here for years and they want to come back,” said Steve Goode, a Death Valley National Park historic maintenance specialist. “It is kind of an anomaly out in the middle of nowhere.”

The bulk of the 2015 storm damage occurred in two buildings: the hacienda-guest house, particularly the basement, which was flooded with 2 feet (0.61 meters) of mud; and the historic garage that is now used as a visitors center. Parts of it were flooded with 4 feet (1.2 meters) of mud and debris.

The storm also destroyed 5 miles (8 kilometers) of the road to Scotty’s Castle, caused water damage campuswide, and wiped out water, electricity and heating, ventilation and air conditioning systems in the main building, Wines said.

“That building is a little higher, so the flash flood didn’t go through it. But the roof leaked, and the flash flood took out the power to the whole site,” she said.

Part of Scotty’s Castle’s charm, as well as its historical and architectural significance, is that every interior and exterior feature of the buildings, down to the door handles, floor tiles, lighting structures and curtain rods, was designed with immense attention to detail.

Conceived by Johnson, as well as architect Martin de Dubovay and designer Charles Alexander MacNeilledge, the Mission Revival-inspired properties have held up well over the years. Even the 2015 storm wasn’t didn’t compromise most of its historic elements.

“This is all redwood,” Goode said during a recent tour of the property, gesturing to the thick, ornately carved doors. “It’s been tooled and burned with a torch, so it’s really unique.”

Prior to its closure, Scotty’s was also full of unusual treasures left from its primary inhabitant, including Scott’s gun collection and pipe organ. Those items are now stored elsewhere in a climate-controlled environment until restoration and repairs are complete.

“There’s a lot of really just priceless stuff and there’s only one of them,” Goode said. “So (Park Service staff) were real concerned about that, and they felt that the best thing to do was to move the stuff off-site.”

In addition to repairing the buildings and the road to Scotty’s Castle, the Park Service is taking steps to prevent future floods from further damaging the structures.

The plan is to construct a series of berms surrounding the grounds so that water and debris flowing from the canyons during rain events don’t hit the buildings, explained Goode.

This step is crucial, considering that the desert climate is prone to erosion and flooding and the grounds lack drains and a sewer system.

Flooding has historically shaped the regional landscape, and Park Service officials anticipate that severe flood events will occur more frequently because of climate change.

Goode and Wines hope to ensure that upgrades and changes to the property, which will be conducted by outside contractors, maintain significant features.

At the same time, park staff recognizes the need to strike a balance between keeping the buildings as they were originally and making necessary changes to ensure the 90-year-old structures will last longer, Wines said.

“In a perfect world, we wouldn’t want (visitors) to see flood control because it has to be historically significant,” Wines said. “But this is not the largest flood that will happen in the future. There will be bigger ones. So if we don’t protect the site from flood damage, then we’re going to lose it entirely.”