Viljo Revell's international breakthrough was winning the first prize in the design competition for the City Hall of Toronto in Canada. One crucial specification for this competition was that there was no limit to what it could cost. This proved to be disastrous, because later on a limit to the cost of the building was enforced. Thus, with great difficulty, Revell had to redesign his building to conform with the financial constraints.

Winning this competition changed Revell's life. He moved his office and family to Canada, and he was forced to divide his time between Toronto and Helsinki. In the beginning the collaboration between the international designers went well, and the work was interesting. But after a while problems began, primarily the question of costs. He became caught between two sides in the political arena; one side supported him and the other side worked against him.

He had to cut the costs dramatically in order to save the project. He simply did not get the support that he needed. In the end it turned out that this financial bickering was due to elections in the near future. This destroyed Revell's belief in positive collaboration.

Revell put all his energy into completing this building. The last picture of him was taken in front of the building site, yet he never lived to see the finished building. He died in Finland in 1964, at the young age of 54.

The City Hall of Toronto consists of four main sections: the Public Square, the Town Council Chamber and the two Office Towers. In front of the City Hall there is a large pool arched by three concrete structures. In the winter they let the pool freeze over for skating, and the area is lit up by a row of lights attached on the underside of the arches.

Viljo Revell and Henry Moore were personal friends and Revell felt that a building was not complete without a Moore sculpture, he considered it the crowning touch. Revell contributed to the placement of a 16 meter high bronze sculpture by Henry Moore, The Archer, in front of the City Hall.

Henry Moore had made a similar sculpture on a smaller scale, in marble, which Marie-Louise and Gunnar Didrichsen acquired for the museum. In this way the synergy between Viljo Revell and Henry Moore was present both in Canada and Finland, and emphasized the understanding the Didrichsens had for Revell.