The Dutch Mountains and the World’s Most Spectacular Mass Timber Buildings

In 2021, Studio Marco Vermeulen proposed twin 426-foot towers built almost entirely from wood, rising above Eindhoven like mountains from a flat landscape. They called it The Dutch Mountains: a swooping U-shaped profile, floors cascading with indoor trees, wide atrium stairs designed to make you want to climb rather than take the elevator.

The project hasn’t broken ground yet. But the world didn’t wait.

In the five years since, mass timber architecture has gone from a promising experiment to one of the most significant building movements of our time. What follows is our ongoing guide to the most spectacular examples.

Sara Kulturhus, Skelleftea, Sweden (2021)

If you had to choose one building to show someone who doubted what timber could do, it would be this one. White Arkitekter’s 20-storey tower in northern Sweden houses a theatre, art gallery, city library, museum, spa, conference centre, restaurant, and a 205-room hotel whose rooms are prefabricated CLT modules stacked between two timber elevator shafts, all under a single roof.

The numbers are staggering: 431,000 cubic feet of wood sequestering approximately 6,000 tonnes of CO2, most of it harvested and milled within 30 miles of the site. But what makes Sara Kulturhus extraordinary isn’t the statistics. It’s the ambition: a 20-storey cultural institution built from local forest, for a city of 36,000 people, in the Swedish north. Dezeen named it “the most significant building of 2021” and revisited that verdict four years later to say the assessment still held.

Ascent MKE, Milwaukee (2022)

When completed in July 2022, Ascent became the world’s tallest certified mass timber building: 25 stories, 86.6 meters, with 259 apartments whose residents live surrounded by exposed CLT panels and glulam beams. The concrete is confined to the base and cores. Everything above is wood.

Korb + Associates Architects designed it, Thornton Tomasetti engineered it, and together they beat the previous record holder, Norway’s Mjostårnet, by just over a meter.

Mjøstårnet, Brumunddal, Norway (2019)

The building that proved it was possible at scale. Eighteen storeys on the banks of Norway’s largest lake: apartments, the Wood Hotel, offices, a restaurant, a swimming pool. Vertical timber fins on the western facade. Materials sourced from the surrounding region’s forestry industry.

Before Mjøstårnet, the question “can you build a real skyscraper from wood?” was theoretical. After it opened, the question became: how high can you go?

Portland International Airport Terminal Expansion (2024)

Perhaps no building in this list is more likely to stop you mid-step and look up. ZGF Architects covered a 9-acre terminal expansion with nearly 35,000 pieces of regionally sourced Douglas fir, arranged in a parametric lattice that undulates like the canopy of a Pacific Northwest forest. Thirty-four branching Y-shaped columns rise 36 feet to support the structure. Forty-nine skylights filter light across 60% of the floor.

ZGF described the roof as “the overstory”: the protective high canopy layer of a forest. They weren’t being metaphorical. Walking through the finished terminal feels like being inside a forest clearing. For the 20 million passengers who travel through PDX each year, this is now their first experience of Oregon.

HAUT, Amsterdam (2022)

Amsterdam’s timber moment: 21 storeys on the River Amstel, 52 apartments, and a design decision that sets it apart from almost every timber building in existence. The load-bearing structure is interior, which means the entire facade can be glass. The exposed timber skeleton is fully visible from the street through floor-to-ceiling windows.

Team V Architecture paired it with irregular balconies and double-height spaces. BREEAM Outstanding, the first residential building in the Netherlands to achieve the rating.

Wood Up, Paris (2024)

For most of the last century, France’s building codes effectively limited timber to low-rise construction. Wood Up changed that: fourteen storeys in the 13th arrondissement, 132 rented apartments, with a glass facade that makes the wooden skeleton fully visible from the street. LAN architects chose this transparency as a deliberate statement.

Their material choices are precise: Douglas fir for external columns (moisture-resistant), beech for interior columns (compressive strength), spruce for beams (bending performance). Three different woods for three structural roles. All French timber, transported to the site by river barge along the Seine.

Rubenstein Treehouse, Harvard University (2025)

Studio Gang’s first expressively structural mass timber civic building, and Harvard’s first. Three stories, but among the most distinctive timber buildings completed anywhere in 2025. Canted exterior columns branch outward as the building rises, the massing literally widening as it goes, until the top floor cantilevers dramatically over the ground. At night, glass transparency and warm timber turn the building into something close to a glowing lantern.

Embodied carbon is 55% less than a comparable conventional building. The 600-person Canopy Hall sits at the top. It’s the closest thing to a treehouse that a serious civic building has ever been.

What Comes Next

The structural frontier in mass timber right now is the concrete core. Most tall timber buildings still use concrete for elevator and stair shafts. Schmidt Hammer Lassen’s Rocket and Tigerli tower in Winterthur, Switzerland, currently under construction, eliminates the concrete core entirely, a structural innovation developed alongside ETH Zurich. At approximately 100 meters, it’s designed to become the world’s tallest residential timber tower.

When that building completes, the question of how high you can build in wood will have a new answer. And then someone will try to beat it.

Originally published March 4, 2021. Substantially updated June 2026.