The Basilica of the Immaculate Conception in Denver is one of dozen of locations open to the public during this year’s Doors Open Denver event, September 21-22. Photo courtesy Cathedral of the Immaculate Conception

At home

The 15th annual event, which runs from September 21-22, offers rare opportunities to explore some of Mile High City’s most inspiring designs, past and present. Here are four websites that you don’t want to miss.

• September 13, 2019

Denver may be known for its natural landscape, but equally inspiring is the built environment we encounter every day. Mile High City is full of beautiful, historic, and architecturally significant buildings that most of us never get to explore – except for one weekend a year during the Denver Architecture Foundation (DAF) annual Doors Open Denver, which takes place on September 21 – 22nd

Headquartered at Union Station, this year’s event features open access to more than 50 locations around the city – some historic, others new – as well as 59 expert-led insider tours that explore everything from local graffiti and murals to the Capitol mansions Hills and unique locations throughout the La Alma-Lincoln Park neighborhood. This year, twelve brand new tours are on the program, as are a handful of new or rarer buildings.

Self-guided tours to open locations are free. Opening times may vary. So be sure to check the Doors Open Denver website before you set off. Insider tours are available on one ticket ($ 12 each) and many sell out prior to the event. We therefore recommend booking your favorites soon. Not sure where to start? Here are some of the must-see open pages of the event:

Photo courtesy Cathedral of the Immaculate Conception

Cathedral of the Immaculate Conception
1535 Logan St.
Open on Saturday, September 21, from 10 a.m. to 4 p.m.

It’s hard to miss this spectacular French Gothic cathedral as you pass the intersection of Colfax Avenue and Logan Street. Referred to as the “Pinnacled Glory of the West” when it was built by Denver firm Gove & Walsh in 1912 (priced at $ 500,000), its entrance features three sets of bronze double doors topped by deep composite arches that draw the eye to a rose window. The cathedral’s 210-foot twin towers, recently cleaned and repaired as part of a large-scale restoration project, are adorned with arcaded bell towers, corner peaks, and curved spiers. The interior of the cathedral is equally inspiring, with 68-foot-high vaulted and vaulted ceilings, ornate spiral staircases, stunning stained-glass windows, and Carrara marble altars.

Photo courtesy Fitzroy Place / Iliff Mansion

Fitzroy Place / Warren-Iliff mansion
2160 S. Cook St.
Open Saturday and Sunday from September 21st to 22nd from 10am to 4pm

A tour of this sprawling mansion in Observatory Park will familiarize you with the features of the Richardson Romanesque architectural style – solid brickwork, Romanesque entrance arch, hipped roof interrupted by two chimneys, and two three-story book towers – as well as design details specified by homeowners enjoying the benefits of the silver boom. The exterior of the house is completely clad in red Arizona limestone. Interior fittings include golden oak paneling and siding, plus 12 fireplaces with carved ceramic tiles and woodwork.

Ketchum building / sprocket design + planning
730 Kalamath St.
Open Saturday and Sunday from September 21st to 22nd from 10am to 4pm

Located in the La Alma-Lincoln Park neighborhood, this mid-century building is currently home to the Sprocket design and construction management company. It is characterized by the use of the thin-shell concrete construction technique, which uses thin concrete arches to span a roof – with little need for central support columns (think the Sydney Opera House). Denver-born civil engineer Milo Ketchum designed this building to house his engineering office and demonstrate the engineering he would specialize in. The five-ton vaulted roof is supported by concrete beams over large rear windows, while a large slope lies above the building. The main entrance shows the ultra-thin profile of the sturdy roof.

Ross Broadway Branch, Denver Public Library
33 E. Bayaud Ave.
Open on Saturday, September 21, from 10 a.m. to 4 p.m.

Chances are you passed this library, located on Bayaud Street between South Lincoln Street and Broadway, or maybe even browsed the shelves without realizing that you observed unique features of the Usonian architectural style. Developed by Frank Lloyd Wright, this style includes low horizontal shapes, dramatic cantilevers, and lots of windows in the back yard to flood the interior with natural light. This one-story structure, designed by architect Victor Hornbein (perhaps best known for designing the Boettcher Memorial Tropical Conservatory at the Denver Botanic Gardens) and built in 1951, shows all of these details: a flat roof with exaggerated eaves, a large cantilever on the east side and operable windows that follow the perimeter of the main interior space, giving this library its warm, inviting feel.

When you go: To learn more about this year’s Doors Open Denver event and to find current schedules, visit