Claim: The William Ayers House is a two and a half story house which failed to make it on the National Register of Historic Places, a Canadian database for historic places established in 1966, after multiple attempts.
Evidence: The house was listed on the National Register of Historic Places on July 8, 1999. 
For the Canadian online database, see Canadian Register of Historic Places. The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance. 
The Canadian Register of Historic Places was created as part of Canada's "Historic Places Initiative". Commencing in 2001, the Historic Places Initiative was a collaboration between the federal, provincial and territorial governments to improve protection of the country's historic sites and to "promote and foster a culture of heritage conservation in Canada".