Oceans and seas, waters outside of national jurisdiction are also referred to as the High Seas or Mare liberum.
Sea Level is 0 feet
the biggest sea wave is a sunarmi which is about 50 or 60 meters tall
Wikipedia says 358 feet
Montreal is about at 500 feet, above sea level
At its lowest point, along the waterfront, Toronto is 76.5 meters above sea level. At its highest point, it's 209 metres above sea level. http://www.toronto.ca/toronto_facts/geography.htm