Officially opened on September 30, 2014, The Advanced Research Complex is a research building at the University of Ottawa, dedicated to multidisciplinary work in Earth sciences, physics and engineering. Guests of Doors Open 2026 will be able to take part in hands-on demos for all ages, conversations with local researchers and laboratory tours. 

The AIDS Committee of Ottawa has served the community for nearly 40 years, providing support, prevention, education and outreach services that promote the holistic well-being of those living with, affected by, impacted by and at risk of HIV/AIDS in Ottawa. Overlooking the Rideau Canal, this home offers services such as subsidized gym memberships, food bank, laundry and office support.

Previously All Saints Anglican Church, the new “Allsaints” is housed in this beloved heritage property and building of national historic significance in the heart of Ottawa’s Sandy Hill neighbourhood. With a commitment to celebrating the building's past and preserving its architectural heritage, Allsaints is looking forward to welcome guests into the space for Doors Open Ottawa 2026.

Spanning 4830 square-metres (52,000 square feet), this brand new, state-of-the-art veterinary centre is purpose-built to deliver comprehensive emergency and specialty care. Supported by a dedicated and experienced team of more than 28 veterinarians — including seven board-certified specialists — Alta Vista has proudly served the pets and families of Ottawa for over 62 years.

This building was constructed on the eve of the Second World War as a church and bomb shelter. During the war, people came to pray to the Theotokos of the Passion icon for the safe return of their loved ones. All the young community men returned from the war. This icon remains a source of comfort during times of need.

In 1978, Ottawa’s mayor recommended establishing a municipal arts centre, arts council, arts festival and a permanent art collection for the city. This building initially served as the Carleton County Court House, purpose-built in 1870-71. It was slated for demolition in 1980, but it was saved by the city and turned into the Arts Court. It officially opened in 1988.

Bayview Yards is Ottawa’s one-stop business acceleration shop — bringing together innovators, entrepreneurs, industry leaders, investors and community members. Built as a municipal works building, it once contained machinery storage and repair shops, stables, offices and stockrooms. Built of reinforced concrete with brick panels, it exemplifies the modern industrial architecture popular in Canada from the 1940s to the 1970s.

The main house here is considered to be one of the oldest homes in Ottawa. The Billings family lived here for five generations. Once a large agricultural property, parts of the estate were given to different family members or sold off. Today, what remains is a museum, several outbuildings and a cemetery for more than 140 community and family members.

Constructed in 1961, this is one of two treatment plants operated by the City of Ottawa to supply drinking water to almost one million people. Its source water is the Ottawa River. The treatment process removes undesirable substances — such as colour, suspended particles, algae, bacteria and viruses. Over the years, the site has seen significant expansion and modernization.

The Bytown Fire Brigade Historical Society is a volunteer-based non-profit corporation dedicated to preserving, interpreting and celebrating the history of firefighting in Ottawa. They collect and maintain historical firefighting artifacts — including vintage fire trucks, uniforms, equipment and photographs — illustrating the evolution of firefighting technology. Through its efforts, they help preserve Ottawa’s firefighting heritage for future generations.

Take a behind-the-scenes tour of Ottawa’s oldest stone building. 2026 is the 200th anniversary of the arrival of Lieutenant Colonel John By in the region and the founding of Bytown. Learn something new about Ottawa's story during the city's 200th anniversary year.

The ByWard Market has been Lowertown’s focal point since 1848. This particular site has served as a market since 1875. The present building is the fifth to house the market. Home to food merchants, specialty boutiques and artisans operating in indoor and outdoor spaces, the ByWard Market Building is a landmark. For Doors Open, enjoy special tours, displays and presentations.

The Canadian Conservation Institute (CCI) and the Canadian Heritage Information Network (CHIN), part of the Department of Canadian Heritage, were created in 1972 to advance and promote the conservation of Canada’s heritage collections. The building houses over 20 laboratories, metal and wood workshops and over 100 offices. Don’t miss “Captain Conservation,” an imposing fiberglass sculpture over the front entrance.

This Centre operates in a beautiful historical building in downtown Ottawa. They provide evidence-informed integrative medicine, research and education across the spectrum of chronic and acute health-care conditions — such as cancer, cardiovascular health, mental health, thyroid health, women’s health, diabetes and more. Their approach emphasizes quality of life, support for the body, care of the spirit and active disease prevention.

The Centretown Mosque was constructed in 1911 as the First United Church — the site of Canada’s first mixed-raced marriage. Since then, it was also the Ottawa Chinese-Canadian Heritage Centre. Today, it is the first mosque to serve Ottawa’s Muslim community. Fundraising campaigns are currently underway to help preserve the site’s history — including two beautiful halls, an organ and stained-glass windows.

Built in 1872, this church was constructed to harmonize with the new Parliament buildings. Named the Cathedral of the Diocese in 1897, it continues to nurture faith in creative and traditional ways. Architectural features include soaring ceilings, magnificent windows and the bell tower, home to the 516-pound bronze bell cast for the original church in 1839.

St. Bartholomew’s Anglican Church was built of local limestone. It remains an active place of worship and a concert venue today, with a history that’s closely intertwined with that of the local community, the city of Ottawa and the nation. Artifacts and windows remind us of those connections — particularly the stained-glass window behind the altar and the magnificent Létourneau organ.

In 1975, CKCU became the first campus-based community radio station in Canada. It continues to be a pioneer in community broadcasting, serving as a voice for many Ottawa identities and communities not served by the mainstream media. Offering over 100 programs in over 10 languages, CKCU is committed to diversity. Come witness live radio in the making!

See inside the broadcast studios of CPAC, an independent, not-for-profit, commercial-free, bilingual media organization that connects Canadians to their democracy. Guests will take part in a guided tour of CPAC's studio, master control, make-up room and learn about the broadcast technology that brings our parliament into nine million homes and directly to the web.

In 1960, NATO and the Canadian Department of National Defense built a satellite communications facility here that provided communications between all NATO countries until 1999 when the site was decommissioned. In 1999, it was purchased by Canadian Space Services Ltd. to serve as its corporate headquarters. Today, interior space is rented to local businesses for meetings, workshops and parties.

The Cumberland Heritage Village Museum provides visitors with an immersive, seasonal experience that showcases rural life in the 1920s and 1930s in Eastern Ontario. Tour an operational sawmill and blacksmith shop, an old train station and caboose, a one-room schoolhouse, a print shop, a 1927 Imperial Gas garage, a 1904 church and several family homes and barns.

This award-winning building serves a representational role for the Ismaili Imamat in Canada, offering a centre for building relationships, enabling quiet diplomacy, and disseminating knowledge and information, while reflecting the humanistic/humanitarian agenda of the Aga Khan Development Network and its associated institutions. Inside, the play of light on transparent and translucent surfaces creates a dynamic visual effect.

Nestled in the heart of Manotick Village, Dickinson Square shares a remarkable past rooted in Canadian history and industrial ingenuity. Run by Watson’s Mill Manotick Inc., Dickinson Square comprises two sites: Watson’s Mill and the Dickinson House Museum. This heritage home explores the lives of the past mill owners. After touring this historical museum, check out the adjacent mill.

The Diefenbunker is Canada’s most significant surviving Cold War artifact. It is an impressive four-storey underground facility that operated as the country’s central communications headquarters during the Cold War, ready at any moment in case of a nuclear attack. Now a museum, the Diefenbunker offers a one-of-a-kind experiential learning environment, coupled with award-winning programs, events and exhibitions. Registration is required.

The Dominion Observatory Campus consists of several scientific buildings used for astronomy, seismology, gravity and geo-magnetism. In 1904, the first building was constructed to house the retractable telescope. In 1905, a transit house was added to the western wing for the meridian circle telescope and transit instruments that were used to determine time, longitude and star positions.