- 📍 Where · At 300 Grant Avenue in San Francisco, one block east of Union Square: a building completed in 2021, currently serving as a showroom for jeweller Brilliant Earth, leased for ten years across four levels and a basement, totalling approximately 2,300 sq m.
- 📅 When · Opening announced for late 2027, operating 24/7. Expansion to other cities starting in 2028.
- 🧖 The circuit · Hot baths, saunas, hammam, cold plunges, gym and studio, live music venue, group tea tastings, contactless longevity treatments, and around ten scanners integrated into the journey.
- 🔬 The scanner · A platform lowers the visitor into the water through a ring of half a million ultrasound sensors: a 3D body map in 60 seconds, without X-rays or magnetic fields. No FDA approval initially: body composition maps, not a diagnosis.
- 🏛️ The architects · Basalt Architects (Reykjavik, the Blue Lagoon) for the concept, Rapt Studio as executive architect, TLEE Spas + Wellness for spa engineering, Myrtha Pools for the basins.
- 💰 The model · Project entirely self-funded by Midjourney, which has no investors · stated goal of 50,000 scanners worldwide by 2031.
Since 2022, Midjourney has been creating images from phrases. In June 2026, the San Francisco laboratory announced something entirely unrelated: a medical division, an ultrasound full-body scanner, and a spa to house it. The first Midjourney Spa will open in late 2027 at 300 Grant Avenue, one block from Union Square, in an interior designed by Iceland’s Basalt Architects, creators of the Blue Lagoon. The idea is captured in a single sentence by its founder, David Holz: “I don’t want it to feel like I’m going to the doctor. I want it to feel like I’m going somewhere nice.” Here is what we know about the venue, the machine, and what this project says about the future of spas.
300 Grant Avenue: a 2021 building one block from Union Square
The address is that of a glass and stone building completed in 2021 at the corner of Grant Avenue and Sutter Street, one of the few new constructions in Union Square in decades. It briefly housed an Arc’teryx store and currently serves as a showroom for jeweller Brilliant Earth. Midjourney has signed a ten-year lease there, negotiated by JLL, across four levels and a basement, totalling approximately 2,300 sq m, with half of the floors reserved for the spa. The neighbourhood, which saw commercial vacancy rise to 22% during the pandemic, is recovering: foot traffic increased by nearly 10% year-on-year in spring 2026, and both AT&T and The RealReal have reopened locations that closed in 2023.
The plan published by Midjourney reads the building from top to bottom. The third floor houses the gym, fitness studio, and service areas. The second floor lines up the cylinders of the scan rooms·nine or ten depending on the documents·each enclosed next to a small pool. The first floor is dedicated to the baths, featuring a large pool bordered by a living wall, glowing columns placed in the water, and the sauna. The basement accommodates the changing rooms and technical facilities. The journey is continuous: guests move from the baths to the scanners without changing out of their robes.
A thermal circuit, a concert hall, and around ten scanners
◆ Renderings by Basalt Architects
The programme is first and foremost that of a contemporary public bathhouse: hot baths, saunas, hammam, cold plunges, a gym, and a fitness studio. These are complemented by a multi-purpose room for live music, group tea tastings, and contactless longevity treatments. The entire facility will operate 24/7, and Midjourney states that it wants to create a place where people can come alone or with friends without thinking about their health. “Scans are a secondary effect,” the company writes. “You barely think about them when visiting the spa. But suddenly, you have a vast library of data on your body.” The price of the scans has not been disclosed; the company, which refers to an “affordable and accessible” service, is testing its subscription models in San Francisco before expanding.
◆ The scan rooms
How the scanner works: water, sound, and 60 seconds
The visitor steps into a shallow pool and stands on a platform, which lowers into the water on tracks at roughly five centimetres per second. They then pass through a ring of submerged sensors: half a million tiny squares, each the size of a grain of sand, which emit ultrasonic waves and record their echoes millions of times per second, “like a dolphin,” Midjourney explains. The waves change shape as they pass from water to skin, fat, muscle, and bone; a cluster of thousands of computers reconstructs these deformations into cross-sections, and then into a 3D body map precise to a fraction of a millimetre, comparable to an MRI and nearly a hundred times faster. No X-rays, no magnetic field, and one minute. The company describes terabytes of data per second of scanning.
The technology is not the one that built Midjourney’s reputation. The core of the scanner comes from Butterfly Network, the American specialist in on-chip ultrasound, with which Midjourney signed a co-development and exclusive licensing agreement in November 2025: $15 million upon signing and $10 million annually, totalling up to $74 million over five years. The prototype aligns 40 Butterfly chips, each bearing 8,960 transducers of 200 microns, in a ring around the body. No FDA approval exists at this stage: the spa will open with body composition maps, without diagnostic pretensions, within the same wellness regulatory framework as full-body MRIs from Prenuvo or Ezra, and Midjourney states it regularly submits its results to the agency to expand its capabilities. Radiologists, meanwhile, highlight the risks of overdiagnosis when scanning healthy individuals every week.
Basalt Architects: making the invisible visible
To design the space, Midjourney turned to the Reykjavik-based agency that shaped Icelandic bath architecture: Basalt, founded in 2009 by Sigríður Sigþórsdóttir, creator of the Blue Lagoon and its Retreat, and led today alongside Hrólfur Cela, Marcos Zotes, and Perla Dís Kristinsdóttir. “Rather than adapting technology to the environment, we asked how the environment could adapt to technology,” explains Hrólfur Cela, who speaks of “making the invisible visible”: the waves and forces that pass through us imperceptibly, translated through movement, light, sound, and water. The scanners become sculptural cylinders, lit from below through the water, around which the spaces are organised; amber and gold tones, mirrored ceilings, and water reflections on the walls give the venue the feel of a bathhouse rather than an imaging centre.
◆ Basalt’s cross-sections
Alongside Basalt, the team is that of a major spa project: Rapt Studio, a San Francisco agency, as executive architect; TLEE Spas + Wellness for journey design; Pritchard Peck for lighting; Myrra Sound Studio for sound; Myrtha Pools and Martin Aquatic for the basins; Tipping Structural and Alphatech for structure and MEP engineering. Jeanine Allpress-Cliffe, president of TLEE, summarises the design philosophy in one phrase: “frequency as medicine”: sound, light, water, and spatial design work together, and the spa is launched as a wellness product, featuring body composition tracking, well before any medical ambitions.
What this project changes for hotel spas
The Midjourney Spa is not a hotel, but it arrives at a time when luxury hospitality is making the exact same bet: transforming the spa into a data-driven space. Marriott has partnered with Therme Group for its major urban bathhouses, Equinox has opened its first resort at AMAALA on the Red Sea around a longevity circuit, and clinics like SHA, Lanserhof, and Clinique La Prairie already sell stays built around health assessments. Midjourney’s difference lies in scale and frequency: a scan every week, in a public bath open at night, at a price the company intends to keep close to that of a spa admission. If the machine delivers on its promises, the multi-thousand-dollar full-body MRI of longevity clinics becomes a neighbourhood service, and hotels that have invested in “longevity” will need to offer something more than access to a scanner: time, place, and hospitality. This is precisely what Basalt has designed.
| Address | 300 Grant Avenue, San Francisco |
| Surface area | approx. 2,300 sq m · 4 levels + basement |
| Lease | 10 years |
| Opening | late 2027 · 24/7 |
| Scanners | around ten |
| Scan duration | 60 seconds |
| Sensors per ring | approx. 500,000 |
| Butterfly Network agreement | up to $74M over 5 years |
| 2031 Goal | 50,000 scanners worldwide |
The roadmap: other cities in 2028, 50,000 scanners by 2031
Midjourney describes the next twelve months as a research phase: refining algorithms and hardware, conducting trials with volunteers, moving to a second-generation scanner, and building this San Francisco “research spa.” In 2028, the company plans to open in other cities and transition to a third-generation scanner with entirely custom silicon; by 2031, it targets over 50,000 machines and one billion scans per month, representing, according to David Holz, some 5,000 locations and $20 billion in investment. The laboratory, which has no investors and states it is funded by its subscriber community, claims the first spa will be profitable within six months. In the meantime, it is opening a waiting list and a call for volunteers for its clinical trials.
Our perspective
The most interesting aspect of this project is not the machine·whose performance remains to be proven and whose very name, “Ultrasonic CT,” borrows from a technology it does not use. It is the architectural reasoning. Midjourney understood that an examination repeated every week cannot feel like a medical exam, and entrusted Basalt with dissolving it into a bath: this is what the Blue Lagoon did for the water of a geothermal power plant, transforming it into Iceland’s premier spa. For hoteliers, the lesson is the same as that of the large urban bathhouses opening everywhere from Reykjavik to Marseillan: the luxury of wellbeing is no longer in the treatment cabin, but in the time spent in the water, and in what the venue knows about you when you step out. See you in late 2027 on Grant Avenue to check whether visitors really think about the scanner “hardly at all.”
Practical information
- Midjourney Spa · 300 Grant Avenue, San Francisco · scheduled opening late 2027 · midjourney.com/medical
- Basalt Architects · Reykjavik · basalt.is
- Also read · the latest spa news and US hotel news on La Revue des Hôtels
