Populus Hotel stands out even among Denver’s prettiest, strangest and most historic buildings.

The newly built structure catches the eye with an exterior designed to mimic an Aspen tree, with 65 different window shapes and a triangular footprint rooted in one of Denver’s busiest intersections, on the corner of West Colfax Avenue and 14th Street.

It’s the nation’s first carbon-positive hotel, developer Urban Villages has said, and the perfect place to celebrate Doors Open Denver 2024. The Sept. 26-Sunday, Sept. 29, event invites the public into local architectural wonders and offers expert commentary on their creation and history.

Attendees can also be the first to attend an event at Populus before it opens to the public on Oct. 18.

“The building is newsworthy across the country because of its sustainability approach and materials, and (for being) carbon positive,” said Meg Touborg, president and CEO of the Denver Architecture Foundation, which produces Doors Open Denver. “That level of innovation and engineering is absolutely remarkable and certainly we wanted to bring fans of Denver’s built environment inside such a novel building.”

The Doors Open Denver gala at Populus takes place from 6 to 8 p.m. on Sept. 28, and costs $150 per ticket. But you don’t have to spend that much to take part. Doors Open Denver features more than two dozen other buildings in Denver, ranging from the Globeville neighborhood in the north to Baker neighborhood in the south, that people can explore and learn about in-person, with a guide, or on a virtual audio tour.

Open sites, where people can tour at leisure, include Five Points’ Blair Caldwell African American Research Library, the Capitol Hill Mansion, and downtown’s Byron R. White U.S. Courthouse. Guided tours take place at the rest of the sites, with a map at denverarchitecture.org.

New this year are open houses at architecture firms, which offer insight into the nitty-gritty of building design and planning. The 20th year of Doors Open Denver is also themed Denver Through Time, with an emphasis on how Denver’s best buildings have changed the city’s identity over the decades. That includes inside tours of historical landmarks such as South Broadway’s Mayan Theatre, but also a spotlight on Colfax, Denver’s long and infamously gritty stretch.

Guided tours of single buildings typically run an hour and a half and cost $20 per person. Not all sites are accessible to people with disabilities. Tickets and more details are available at denverarchitecture.org.

“We’re also looking at how Denver is reanimating buildings in new ways, because the city is really a leader in adaptive re-use, as you can see at Union Station,” Touborg said. “The new, $20 million Cleo Parker Robinson Dance project is another great example, which is why we’re touring their construction site, a former church, with (Robinson) talking about its history.”

The Robinson tour costs $55, since it includes additional programming and a performance. Doors Open Denver also features a keynote lecture with architect Vishaan Chakrabarti at Denver Art Museum (on Sept. 26, with tickets for $65), a photo-contest reception at Colorado Photographic Arts Center (also Sept. 26; free), a cocktail reception (Sept. 26, $95, at a private residence), and a wrap party at the Posner Center for International Development (free, Sept. 29). Other events include a screening, book signings and author appearances.

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