781 centimeters is equivalent to 307.48031496 inches.
To put this into perspective, 307 inches is slightly longer than the length of a standard twin size bed (75 inches), but slightly shorter than the length of a full size bed (80 inches). It is also about the same length as a standard doorway (roughly 308 inches).
In terms of everyday objects, 307 inches is about the same length as two average-sized adult men lying end to end (roughly 6 feet 4 inches each). It is also slightly longer than the height of an average adult giraffe (around 18 feet).