The Canal is built up higher than the oceans on either side (25.9m above sea level) because the oceans on either side of Panama have an eight-inch difference in sea level. This means that in order to cross from one side to the next, a ship must be elevated up to the maximum height of the canal on one side, and then lowered back down to sea level on the other side (brilliant!). And the real kicker is that the Canal itself consists of fresh water that is fed