The Music Hall was originally built as Centenary Methodist Church in 1868. Designed by architect Albert Harvey Hills, the building is a stunning example of Victorian-romanesque style. Now the New Vision United Church (The Music Hall) is a designated building in the City of Hamilton. It boasts soaring ceilings, glorious acoustics, a wrap-around mezzanine and massive stained-glass windows. 

The Niagara Lodge No. 2 is the oldest Masonic lodge in Ontario. It is also the site of the first legislature of Upper Canada and the site of the first hospital in Newark, founded by Col. John Butler. During Doors Open, come and explore the museum of Masonic artifacts not regularly available to the general public.

The Niagara Masonic Memorial Temple Association welcomes you to their first Doors Open Event. Originally built in 1891 as St. George’s Ward Primary School, this St. Catharines landmark educated generations of local students before closing in 1952. The building was later transformed for community use and now houses the Niagara Conservatory of Music and four masonic lodges.

Located on the banks of the Niagara River in a heritage building that formerly supplied water to Niagara-on-the-Lake, the Niagara Pumphouse Arts Centre connects the community through visual arts programs, exhibitions and events. The Niagara Pumphouse Art Centre Association was formed in 1990, and the building was restored and converted to this visual arts centre in 1994.

Decew Falls Water Treatment Plant has been processing drinking water for residents since 1876. As Niagara Region’s largest water treatment facility, it is designed to treat 227 million litres of water per day. The site is unique compared to other water treatment plants in Ontario due to its gravity fed distribution system. Pre-registration for all tours is required.

Founded in 1877, the Niagara-on-the-Lake Lawn Bowling Club is one of the oldest in Canada. Before this club was built, they bowled on the grounds of the Queen’s Royal Hotel. Today, they are located at the adjacent community centre, where visitors can learn more by stopping by the Mori and Simpson rooms during Doors Open.

Explore this fine example of one of the few remaining early pioneer timber-constructed log cabins in Haldimand County. The cabin was built circa 1835 by Thomas Nicholas for his family of 13. Enjoy guided and self-guided tours to learn more about Haldimand's pioneer history.

The North West Company Lock is located at the foot of Huron Street. It is actually two structures built almost 100 years apart. The stone replica lock seen today was built in 1896 and lies over the floor and framework of the original lock built in 1797. The lock was built to help laden canoes and boats navigate the rapids.

Nuit Blanche London 2026 transforms Dundas Street into a vibrant space for exploration. As a dynamic urban canvas, it invites visitors to experience the city in unexpected ways. This year’s theme, "This Is Not a Landmark", challenges traditional ideas of public space, encouraging fresh perspectives on how we define, use and interact with the urban environment around us.

The Nursing Simulation Centre allows York University's nursing students to achieve their professional development/learning goals. Located on the third floor of the Health, Nursing and Environmental Studies building, it can be divided into two unique spaces — the Nursing Skills Lab and the Computer Skills Lab. The Nursing Skills Lab houses adult medical-surgical beds, a pediatric area and two isolation rooms.

This studio features the work of Helen Grace Agalawatte, inspired by journeys north of Toronto and the rugged beauty of Ontario’s lakes, rocks, and forests. Working on cradled wood panels, her layered paintings, created using unconventional tools, capture the wild, unpredictable energy of the landscape. 

The Oakwood Library was constructed in 1913 as the new school for Mariposa School Section 12. Operating as a school until 1985, it became the Mariposa municipal administration building and then, in 2002, the Oakwood branch of the Kawartha Lakes Public Library. Join us to explore the building and learn about this historical institutional building in the hamlet of Oakwood.

The imposing Old City Hall was Toronto’s third city hall. The lobby features one of the city's few secular stained-glass windows. Original gargoyles were replaced in 2002 with replicas. And, in 1925, a cenotaph was erected outside to honour Torontonians who died in the First World War (later updated for veterans of the Second World War and the Korean War).

The Old Don Jail served as a prison for 113 years, closing in 1977. After years of stagnation, the property was purchased by Hennick Bridgepoint Hospital as part of its new campus. The modern hospital, with its 150-year history in Toronto's Riverdale community, is connected by a glass bridge to the historical jail, which now serves as its administrative building. (Photo: Richard Adams)

This was a working fire station until 1980. The designated structure has been preserved and moved to Biidaasige Park in 2021 where it reopened in January 2026 as a community building staffed/programmed by the City. During Doors Open, explore the newly renovated building, see original architectural drawings, discover surrounding nature walks, and learn about future developments for the park.

The tennis pavilion at the Ottawa New Edinburgh Club serves as the social and operational hub of the club’s vibrant summer tennis program. Set within a scenic parkland environment near the Ottawa River, the pavilion overlooks a well-maintained collection of outdoor courts and provides a welcoming space for players, members and guests.

Explore the Ontario Forest Research Institute (OFRI), one of the Sault’s most beautifully designed buildings. Constructed with local maple, granite and glass, it offers a unique work environment with natural light and a reminder of its northern Ontario location. OFRI is a Ministry of Natural Resources workplace, supporting forest research related to climate change, genetic diversity, invasive species and more.

Headquarters of the Ontario Heritage Trust, the building features two gallery spaces with mezzanines, an oak-panelled oval board room and a restored manually operated elevator. Often chosen for filming locations, it has appeared over the years in various productions like What We Do in the Shadows and Serendipity. Special programming: Participate in a "plaque-tivity" and make suggestions for future provincial plaques.

Built in 1898, DeCew Generating Station 1 (GS1) is one of the oldest continually running hydroelectric power generating station in Canada. More than 125 years after it was built, GS1 continues to help OPG generate safe, clean, reliable, low-cost power for Ontario. Today, the plant is a working piece of Canada’s hydroelectric heritage.  Pre-registration Required; Onsite Parking Not Available

The Airport Armoury supports 'B' squadron training for members of the Ontario Regiment (RCAC), providing space to conduct vehicle and equipment maintenance, as well as related courses. Speak with members about their roles and experiences within the Canadian Armed Forces.

This museum has been an art, culture and heritage hub in the heart of Orillia for over 25 years. Located in downtown Orillia, the clocktower of the Sir Samuel Steele Memorial Building is a beacon for the museum. The museum’s mission is to provide inclusive space to engage community, inspire creativity and celebrate culture, by exploring art and history.

The Oro African Methodist Episcopal Church, built in 1846-49, is a designated National Historic Site. It is one of the oldest African log churches still standing in North America, standing as a testament to both the Black settlers who carefully maintained it for nearly 75 years and the passionate community volunteers who have worked diligently to preserve it.

Built in 1874 by local builder Thomas Orr Sr., this elegant Italianate home features tall arched windows, decorative brickwork and wide eaves with ornate brackets. Once a private residence, it now serves as the Orr Insurance & Investment head office, reflecting Stratford's rich architectural heritage and the Orr family's long-standing community legacy.

Osgoode Hall — home of the Law Society of Ontario and the highest courts of the province — opened in 1832 and remains a Toronto landmark and symbol of the law in Ontario. The 1867 fence, renowned for its peculiar gates, surrounds the property and its landscaped grounds. Download the self-guided tour or speak with the knowledgeable volunteers. (No tripods allowed.)

Operating since 1973, the Osgoode Township Museum presents the story of Ottawa South’s agricultural and rural heritage. The main museum building is a mid-century two-room schoolhouse that holds the collection of nearly 11,000 artifacts. Explore the galleries, gift shop and research library during your visit. Then step outside and wander through the Agricultural Barn and discover their vast farming collection.