The Cathedral of the Transfiguration is a Slovak Byzantine Rite Roman Catholic located in Markham, Ontario.
The Cathedral was conceived and funded by Stephen B. Roman, a Slovak immigrant to Canada. Roman both funded and designed the building, modeling the structure on the church in Velky Ruskov, the Slovak village he was raised in.
Among its features is the world's largest three bell carillon, with the French made bells by the Fonderie Paccard, weighing 32,000 pounds, and 300 cm diameter. The mosaics are reputed to contain about 5 million pieces. The central tower rises 63 metres (about 20 storeys) and is topped by a gold onion dome.
The Catheral was designed by Donald Buttress, a renowned architect whose claim to fame is overhauling Westminster Abbey. This site became the first church in North America to be consecrated by Pope John Paul II during his 1984 trip to Canada.