Singing Christmas Tree upon the location. Since then, the singing Christmas tree concept has spread to Canada, the Philippines, South Korea, Switzerland and Sri Lanka. The most attended tree takes place in Knoxville, Tennessee, with 60,000 attendees in 2007. The first Christmas trees came to the United States in the 1740s from Moravian (now part of the Czech Republic) settlers. In 1851, the first commercial tree lot in the United States was set up in New York City. President of the United States Franklin Pierce set up the first Christmas tree in the White House in 1856. Artificial trees were first developed in
White House Military Office residence away from the White House. That same year, the White House Communications Agency was formed to assure that the President always had access to safe, secure, and reliable means of communication. Two years later, President Franklin D. Roosevelt called for the creation of the Presidential Pilot's Office (renamed the Presidential Airlift Group in 2001) to provide air transportation to the President and his staff. The White House Medical Unit was established in the West Wing in 1945. The White House Mess, also contained in the West Wing, was established in 1951 and has been run by the Navy ever