The Ontario Science Centre, originally the Centennial Centre of Science and Technology, is a science museum and educational organization temporarily located at Harbourfront Centre in Toronto, Canada. Site The original site, located near the Don Valley Parkway on Don Mills Road in the former city of North York, is about northeast of downtown Toronto. Built into the side of a ravine formed by a branch of the Don River, the museum consisted of a series of buildings constructed at different levels on a steep hill and connected by escalators. Large windows provided views of the surrounding forest and river. It was closed by the Government of Ontario in June 2024 after an engineering report identified a high risk of roof collapse. The closure and relocation plans drew public opposition.
In 2023, Ontario Premier Doug Ford announced a government plan to relocate the Ontario Science Centre to a new, smaller building at Ontario Place on the Toronto waterfront.
The Ontario Science Centre opened KidSpark at Harbourfront Centre in 2024. Harbourfront Centre serves as its interim home—with an expansion planned for Summer 2026—offering interactive exhibits until the Ontario Place site is ready. Premier Doug Ford has announced in May 2026 that they have broken ground on the new site and are committed to opening in 2029.
History
Construction and opening Planning for the Science Centre began in 1961 during Toronto's expansion in the late 1950s and 1960s. In August 1964, Ontario Premier John Robarts announced the creation of the Centennial Centre of Science and Technology as a Centennial Project. Toronto architect Raymond Moriyama was hired to design the site.
Construction started in 1966 with plans to open the Centennial Centre of Science and Technology as part of the Canadian Centennial celebrations in 1967. However, construction was not completed by 1967, and the Science Centre did not open to the public until two years later, on 26 September 1969. The final cost of the project was .
The official opening was held on the morning of 27 September and attended by a small group of guests, followed by an opening to a larger group of 30,000 guests in the early afternoon. It then opened to the general public on 28 September, drawing 9,000 visitors. Its advertising slogan at launch was "Come see what would happen if Albert Einstein and Walt Disney had gotten together."
Upon opening in 1969, the Science Centre claimed to have adopted a hands-on approach to science, aligning with the interactive educational philosophy seen at institutions such as San Francisco's Exploratorium (1969) and the Michigan Science Center (1970) in Detroit.
The original exhibits included a simulation of the LEM landing on the Moon, a tic-tac-toe game played against a computer, and a simulated hot cell. The museum also had an outreach program, which included touring vans that visited schools around the province.
The majority of the exhibits at the Science Centre were interactive, while others were live demonstrations, such as metalworking. The communications room contained many computerized displays, including a tic-tac-toe game, run on a PDP-11 minicomputer. By 1974, the OSC hosted around 250,000 students on field trips annually.
Operations from 1990 to 2022
International contract (1990) In 1990, the Ontario Science Centre announced a contract with Oman to design a children's museum. At the time, the Centre had agreed to boycott Israeli goods and services while under contract. The agreement was later amended to specify that all goods sold to Oman would be produced in North America. The Centre's director-general, Mark Abbott, was subsequently dismissed for signing the original contract.
In 1996, a redesigned entryway was opened, which contained an Omnimax theatre. Beginning in 2001, a redesign funded by a mix of public and private capital began. It was completed in 2007.
Renewal: Agents of Change (2001–2007) Beginning in 2001, the Science Centre launched a major renewal initiative known as Agents of Change, to modernize its facilities and programming. The project renovated approximately 85 per cent of the Centre's public space and created seven new experience areas. Funding for the initiative totaled $47.5 million and included contributions from the Government of Ontario, private-sector companies, and individual donors.
The Agents of Change transformation was completed in 2007, marked by the opening of the Weston Family Innovation Centre and the TELUSCAPE plaza.
COVID-19 outreach (2020) During the COVID-19 pandemic, the Science Centre received $500,000 from the Government of Canada to support efforts promoting COVID-19 vaccine uptake among children and their families.
Facility decay, replacement plans, and closure
From 2023 until the Don Mills site's closure, a shuttle bus ran from the Science Centre's entrance to the main exhibit area on the museum's Level 6, because of structural decay in the pedestrian bridge that led to the exhibit area, located at the bottom of the Don River ravine.
On 18 April 2023, Ontario Premier Doug Ford announced the provincial government's plan to relocate the Science Centre to a new facility on the grounds of Ontario Place on the Toronto waterfront. This announcement drew public criticism due to concerns about potential downsizing and exhibit losses. Both the Architectural Conservancy of Ontario and the Toronto Society of Architects condemned the relocation plans, while the grassroots group Save Ontario's Science Centre organized rallies and campaigns to oppose the government's decision. Toronto City Council also sought to keep the Science Centre at its original location.
In December 2023, the Auditor General of Ontario concluded that the government's decision "was not fully informed and based on preliminary and incomplete costing information, and had proceeded without full consultation from key stakeholders or a clear plan for the existing site".
On 21 June 2024, the Ministry of Infrastructure announced the immediate closure of the Don Mills location, citing an engineering report revealing water damage affecting two to six per cent of the building's roofs. The report estimated that repairs would cost at least $22 million and take two years to complete. Safety concerns about the roof material in question, reinforced autoclaved aerated concrete (RAAC), had caused the temporary or permanent closure of hundreds of buildings in the United Kingdom in 2023. While roughly 400 public buildings in Ontario contain RAAC, the Science Centre is currently the only one in the province closed over these concerns.
The Ford government expedited its plan to relocate the Science Centre to the waterfront, targeting a 2028 opening, and later revised to 2029, with a temporary location slated for January 2026. This decision drew criticism from Moriyama Teshima Architects, the firm founded by the Science Centre's original architect.
The architects offered pro bono design consulting services for the Government of Ontario to support immediate repairs to the roof, and called for other organizations to join the effort to facilitate repairs. Private donors, including computer scientist Geoffrey Hinton, offered up to $1 million to fund repairs for the existing facility, but the province did not respond to these offers.
Disputes over closure rationale In May 2025, the Canadian Architect magazine obtained the drafts of the structural report done by the Rimkus Consulting Group. Dated to the spring of 2024, the drafts recommended routine repairs of the roof with a strong emphasis on RAAC panel replacement, a straightforward project that had already been put into effect for the most critical panels. Although there was mention of "full closure" in the final report, restricted access would only be needed for a "minuscule portion" of the high-risk roof areas. The report drafts are considered alongside a 2024 Global News story that highlighted frequent communication between Rimkus and Infrastructure Ontario before the report's official submission. Critics argued that the "supplemental risk mitigation options" were only inserted in response to political pressure. The suggestion of restricted access and the potential consequences of preventing repairs appear to be the primary justifications for a full closure of the centre.
Temporary locations and future of original site By 31 October 2024, most of the exhibits had been moved to storage facilities in northern Toronto and Guelph, while the animals and plants had been transferred to the Toronto Zoo in the eastern part of Scarborough and The Village at Black Creek in the western part of North York. Temporary pop-up exhibits have since opened at Sherway Gardens in the southern part of Etobicoke and Toronto's Harbourfront Centre by the Toronto waterfront.
In December 2024, the Auditor General (AG) of Ontario questioned the financial prudence of the relocation. Contrary to the Ford government's business plan analysis, which projected $257 million in savings over 50 years, the AG found that relocation costs have already exceeded the anticipated savings, reaching approximately $400 million., the area around the Science Centre is being developed for the upcoming Ontario Line, which will pass nearby in an overhead track. Deforestation and land development work have been occurring at the site. The station for the line and for Line 5 Eglinton that were originally to be known as "Science Centre station" have been renamed to "Don Valley Station". Security presence, as well as construction and repairs on the roof of the building have also been noticed, though Infrastructure Ontario stated that direct roof access for snow removal was "unsafe" following record snowfalls in January 2026. All of this continues with no clear plan from the province for what will become of the original building.
Following that heavy snowfall in January 2026, renewed calls to reopen or find an alternative use for the building occurred, with continued opposition from the government of Ontario. This followed previous reports that continued maintenance work was occurring at the building and plans for a temporary site at the Harbourfront Centre. No confirmed usage for the original building has been announced as of 2026. In February 2026, Premier Ford unveiled the designs of the new building and announced that a contract had been awarded for its construction. It will cost an estimated $1 billion and will be smaller than the original facility, with an area of about .
Original grounds Building
Designed in the early 1960s, the original buildings were built in the Brutalist architectural style. The building complex is made up of three main buildings connected by a series of bridges and escalators set within more than of parkland. The buildings were constructed while avoiding removal or damage to the mature trees in the area, so that "the buildings seem to fit naturally into their environment". They follow the natural contours of the Don River ravine, into which the Centre descends. Ontario's only IMAX Dome theatre opened in 1996.
The Great Hall is an event venue at the Ontario Science Centre and is home to Cloud, a large, computer-controlled kinetic sculpture by Toronto installation artist David Rokeby, which consists of an array of blue and transparent squares that rotate in various ways to simulate the three states of matter: solid, liquid and gas.
For much of its history, the Science Centre has hosted a demonstration amateur radio station. Formerly located in the Hall of Space, the station was later relocated to Level 4 of the Centre, next to the elevator. The station has the call sign "VE3OSC", and licensed amateur radio operators volunteer there daily from 10 a.m. to 3 p.m.
Plaza