True North

True geographic north lies at the top of modern maps (although some ancient maps had east at the top!). True geographic north is the area where lines of longitude converge (since longitude lines run north-south). But compasses don´t point to geographic north - they point to magnetic north. Depending on where you are on earth, the difference between the two norths can be inconsequential or significant. That´s why many maps show the magnetic declination at the bottom. It tells you how far magnetic north deviates from geographic north in the area of the world shown by that particular map.