As you leave artist Torreya Cummings’ “Notes From Camp” installation at the Oakland Museum of California, a sign resembling an Old West newspaper proclaims, “Every Town is a Ghost Town/ If You Live There Long Enough.”

Ain’t that the truth.

Cummings uses this observation as the coda to an immersive mashup, where a miner’s shack, a cave with plexiglass walls and beanbag boulders overlap. But it resonates with the experience of anyone who comes to know a city and experiences it long enough to be jarred by phantom landscapes and the memories they evoke.

Many of the memories are of the people you associate with the place, the ones who moved, were forced out or fell victim to scourges such as AIDS. But it is the buildings that trip the senses — three-dimensional witnesses to how the past and present collide.

Whenever I’m on the 200 block of Grant Avenue, my stride slows down at Tillman Place. Down the alley there’s a small vacant storefront that was home to Charlotte Newbegin’s bookstore, a curated wonder long before the word “curated” was in vogue and a nook that felt impossibly exotic to a kid on day trips from Walnut Creek. Newbegin died in 1989 and left the store to an employee, Jim Armistead, who held off the onslaught of national chains until the millennium loomed.

I could turn west and encounter the bleak, blank marquee above long-gone Marquard’s newsstand, which once held a neon sign. Too painful, so I head east on Market Street — drawn by the ghost of Stacey’s, a three-story bookstore that was a temple of clean efficiency until 2009. Quietly smart, not musty but modern, it always seemed to good to be true. Now the space holds a CVS.

In between Newbegin’s faint echo and Stacey’s clean aura there’s the corner that held Cafe Capriccio in the early ’90s, urbane and snug. Also, the most recent loss, Jeffrey’s Toys at the base of the Monadnock Building on Annie Alley. A great destination for my daughter to explore on her visits downtown — and felled in 2015 for a still-empty space where the windows proclaim “Flagship Restaurant Opportunity.”

This is small change compared to the razing of the Fox Theater in 1963 (before my time, still a sore point for older locals), or how the Old Main became the Asian Art Museum after a New Main rose just yards away. Yet they’re orientation points on my personal map as surely as the Walgreen’s at Columbus Avenue and Bay Street will always be the shell of Tower Records, a late-night oasis for decades.

Orientation as dislocation, the nostalgist would argue, changes that make us feel unmoored from our setting. Except that the real culprit is the passing of time. We grow older. Those ghosts aren’t how San Francisco (or any city) “ought to be.” They’re spirits from the city of our youth, the places where we inhabited distant phases of our lives.

In the case of “Notes From Camp,” the installation grew from a topic that Cummings first confronted as a student at California College of the Arts: “What are the leftovers of history, and how do you navigate that space?”

Cummings grew up in the Central Valley before heading to UC Davis and spending the last 10 years in the Bay Area.

That’s why “Notes From Camp” sets a miner’s cabin next to a cave but then veils spaces in Mylar and fishnet. There’s a disco ball above the cave’s black Plexiglas walls, while the “rocks” are customized beanbags with a shiny nightclub glow.

“Art should be a portal into another dimension, where you can make associations that aren’t necessarily linear,” says Cummings, who has a studio in West Oakland. “You carry places with you, and you encounter places that you remember as something else.”

Amid the juxtapositions, and the bittersweet loss, our ghost towns grow ever more dense.

Take Ghirardelli Square or the Cannery near Aquatic Park. In the 1960s, each of those brick-clad bastions of food production was reborn as an enclave of shops and restaurants, every bit as trendy as the Ferry Building today. But in the San Francisco of 2017, Ghirardelli Square’s main draw for locals is the ice cream. The Cannery has been colonized by the Academy of Art University.

Layer upon layer upon layer.

This week I paused on First Street near Market, where Oceanwide Center will rise — a 61-story tower designed to hold 109 ultra-luxe condominiums perched atop roughly 1 million square feet of office space.

To make way for the futuristic tower to be, three buildings were torn down. In the process, faded advertisements were exposed on the neighbor to the west, a four-story brick structure from 1906. One announces a printer that was housed in the building when it opened, Gilmartin Co. The other is a firm I can’t quite make out.

The names have been covered since 1917, when the now-gone neighbor on First Street went up. In another year or so, they’ll likely be covered again. But I’ll always know the blast from the past that briefly hovered above the future. Another piece added to my own private ghost town, an impression that will remain.

Place is a column by John King, The San Francisco Chronicle’s urban design critic. Email: jking@sfchronicle.com Twitter: @johnkingsfchron

On display

Torreya Cummings’ “Notes From Camp (a.k.a. Transdimensional Ghost Town Discotheque)” is on view through May in the Gallery of California Art at the Oakland Museum of California, 1000 Oak St., Oakland. For more information go to www.museumca.org.