Back in 2021, we rounded up ten of the most ambitious architecture projects then on the drawing board - buildings that were still proposals, under construction, or fighting for planning approval. Five years on, some of them got built. One, famously, never will. Here's the original lineup, with an honest update on where things actually stand - plus two things that weren't even on the radar back in 2021.
A Cardiac Center With a View of the Pyramids
Egypt is known for more than its pyramids and luxury hotels like the Baron Palace and Cairo Marriott. In 2021, Foster + Partners was deep into construction on the Magdi Yacoub Global Heart Centre - an international cardiac hospital on a site with unobstructed views of the Pyramids of Giza, next to Zewail City of Science and Technology.
The design reads more like an oasis than a hospital: extensive greenery, an artificial lake, and a passive-design strategy built around patient recovery. Update: the project has continued through construction in the years since and, according to the Magdi Yacoub Foundation, has been preparing to welcome its first patients - one of the few projects on this list that appears close to fully realized.
A Sculptural Bridge from Zaha Hadid Architects, Vilnius
Green Connect was a large-scale reconstruction of a Vilnius rail station, tasked with improving the space visually while weaving in new transit connections. The centerpiece: a sculptural pedestrian bridge spanning 150 meters of track and platforms, 10 meters tall and 46 meters wide, meant to stitch two parts of the city back together with green space and cycling paths built in.
MAD Architects' One River North, Denver
Chinese firm MAD Architects broke ground on a residential tower in Denver built around what they called a "landscape fracture" - a crack running the full height of the building, filled with greenery, giving the impression that plant life is quietly splitting the tower in two. It's an effect that, at the time, had no real precedent anywhere else in the world. The plan called for sixteen floors of housing plus supporting infrastructure.
A Luxury Tented Resort in Saudi Arabia
Local authorities were counting on the Ashar Tented Resort - proposed for AlUla, an area often described as an open-air museum - to help drive tourism to the region. The "tents" themselves were designed in brick and rammed earth rather than fabric, spread across the Ashar valley alongside restaurants, a spa, and a rock-framed pool - built around the idea of luxury that stays in conversation with the site's centuries of history.
MAD's "The Star," Hollywood
A flattened sphere dropped into the middle of Hollywood's rectilinear skyline - MAD's answer to conventional office architecture. Hanging gardens, an upper level reachable only by funicular, and a deliberate refusal to look like anything else nearby. The original timeline called for completion in 2026.
Fifteen Fifteen, Vancouver
A 202-unit residential tower that started pre-sales in November 2021, before construction had even begun. The building's top-floor Observatory Residences were designed around panoramic views over the city, alongside a mix of studios and larger three-bedroom units.
Kyiv's Fayna Town Keeps Growing
One of Kyiv's better-known residential complexes, Fayna Town had already opened its first phase by 2021 but continued expanding - its own infrastructure, bike paths, parks, and round-the-clock security supporting a "city within a city" concept. Staggered building heights and generous panoramic windows were designed specifically to bring natural light into every unit.
Arsenalna Square's Ongoing Transformation, Kyiv
Arsenalna Square has changed shape repeatedly across its long history, and the reconstruction underway in 2021 - a dry fountain, a cherry-blossom alley, unified paving and the removal of stairs and abrupt grade changes to tie the space together - was one more chapter in that story.
Shell House, Black Sea Coast
An eco-project proposed for Ukraine's Mykolaiv region: a cluster of mussel-shell-shaped houses across 670 square meters, finished in wheat-toned colors chosen to echo the surrounding coastline, with a pool built in alongside direct sea access.
Foster + Partners' Tulip - Rejected
The most contested project on this list, and the one with the clearest ending. Norman Foster's tulip-shaped observation tower had been proposed for the City of London back in 2018, planned as the UK capital's second-tallest structure with public space and a viewing deck at its crown. Update: UK authorities rejected the project for good in November 2021, citing its embodied carbon footprint and potential harm to the historic skyline around the Tower of London. The Tulip was never built, and it's not coming back.
New Since 2021: Foster + Partners' JPMorgan Chase Tower Opens in Manhattan
Nothing on the original list was as big as this. Foster + Partners' 270 Park Avenue - JPMorgan Chase's 60-story, 423-meter global headquarters in Midtown Manhattan - officially opened in October 2025. It's now New York's largest all-electric tower, hydro-powered with net-zero operational emissions, replacing the bank's 1960s SOM-designed headquarters on the same site. The bronze diagrid facade and stepped, symmetrical setbacks read as a modern nod to the city's Art Deco towers, and the building offers two and a half times more public space at street level than what it replaced.
New Since 2021: The Sphere Question
The original Las Vegas Sphere opened in September 2023, well after our first list - but the bigger story is what's happened since. Sphere Entertainment has announced a $1.7 billion Sphere Abu Dhabi on Yas Island, plus a smaller venue at National Harbor near Washington, D.C. A planned London Sphere was scrapped in 2024 after the city's mayor blocked it.
The expansion raises real questions the original Vegas building didn't have to answer alone: as of late 2024, Sphere Entertainment wasn't yet profitable and was burning through cash fast, even as revenue kept climbing. Each venue is also a genuinely massive content-production undertaking - the immersive LED "Exosphere" technology demands enormous amounts of custom-built footage and, by extension, enormous amounts of energy to run. Whether the format scales profitably beyond Las Vegas' tourist economy, or whether it stays a one-city novelty, is still an open question five venues into the experiment.
The Takeaway
Ambitious architecture proposals are exactly that - proposals. Some, like the Magdi Yacoub Global Heart Centre or 270 Park Avenue, make it all the way to opening day. Others, like the Tulip, never clear planning approval no matter how striking the renderings. And some, like the Sphere format, get built successfully and still have to prove the business model works at scale. It's a useful reminder for any large project: the design is only the beginning of the story. For more of our take on ambitious residential and architectural work, see our first Best Architecture of 2021 roundup and our piece on Hudson Yards.
