64 bits fit neatly onto an 8×8 matrix of black/white squares. Those 64 bits, naively encoding latitude/longitude, will at *worst* locate any point on the planet to within 1cm.

Equatorial circumference: 40,075,017 m
Meridional circumference: 40,007,860 m

Assuming 32 bits per measurement;
Longitudinal precision: 40075017 m / (2^32) in cm = 0.9330692 centimetres
Latitudinal precision: 40007860/2 m / (2^32) in cm = 0.46575279 centimetres
We don’t even need that 64th bit; latitude will fit into 31.

If you want to physically encode that point onto a physical object/location, each of those square ‘bits’ can’t be larger than 1.25mm wide.

Smaller if you leave some space to write “YOU ARE HERE”