In 1981 , the Château Montebello hosted the 7th G7 summit ; and leaders such as Pierre Trudeau , Margaret Thatcher , Ronald Reagan and François Mitterrand were guests along with the aides and security staffs traveling with these national leaders . In August 1983 , the Bilderberg Group held its annual meeting at the resort . In October 1983 , the resort hosted the ministerial meeting for NATO 's Nuclear Planning Group
7th G7 summit
7th G7 summit
Château Montebello