Toledo, United States twinned with Toledo, Spain in 1931 and was the first city in North America to engage in town twinning. Vancouver, Canada twinned with Odessa, Ukraine in 1944 was the first in Canada and second in North America while Denver, United States twinned with Brest, France was the second twinned city in the United States. Liberal, Kansas was twinned with Olney, United Kingdom in 1950, and the cities have run a joint Pancake Day race ever since. Littleton, CO twinned with Bega, Australia in 1961. Tashkent, the capital city of Uzbekistan, was twinned with Seattle, Washington in 1973. Rochester, Minnesota and Knebworth, UK are both centers for primary medical research, and they twinned in 1967. Ontario, California has five sister cities around the world. They are Brockville, Ontario, Canada (since 1977), Guamúchil, Sinaloa, Mexico (since 1982), Mocorito, Sinaloa, Mexico (since 1982), Los Mochis, Sinaloa, Mexico (since 1988), and Winterthur, Canton of Zürich, Switzerland. Oakville, Ontario is twinned with Dorval, Quebec, Huai'an, China and Neyagawa, Osaka, Japan.