Essential travel, as defined by Canadian and US regulations, includes travel for employment or education purposes.[21] "Non-essential" travel to Canada, includes travel "for an optional or discretionary purpose, such as tourism, recreation or entertainment."[22] The U.S. Department of Homeland Security issued defined non-essential travel to include "tourism purposes (e.g., sightseeing, recreation, gambling, or attending cultural events)" and gave an extensive, non-exhaustive definition of what sorts of travel qualify as essential.[23]