>what is the difference between True and Magnetic, seems the magnet one is the true one so the True one must be a lie.
>But also I wonder which one the chose for the egypt pyramid, the true one or the lie?
The builders of the pyramid would have used true north which they derived through astronomical observations. The celestial north pole is evident from apparent stellar motions and shares an axis with the planet. Thus the celestial pole 'points' to the planet's true north.
The planet's magnetic field is generated by the rotating molten core. The magnetic field has magnetic poles at the points where the field lines converge. A compass aligns itself with a line drawn between these magnetic poles. These magnetic poles are completely independent of the rotational poles along earth's axis. Since magnetic measurements were made during the heroic age of arctic exploration when teams of men man-hauled heavily-laden sledges and magnetometers in 1831, the north magnetic pole has wandered from Arctic Canada to the Arctic Ocean.