684.93 cm = 269.68 inches
This is slightly longer than a standard Twin or Single size bed (75 inches) and slightly shorter than a California King size bed (84 inches).
It is also approximately the length of 5 standard adult baseball bats (34 inches) lined up end to end.
Additionally, it is roughly the height of a standard adult male African lion (at the shoulder) and about the height of a standard adult female giraffe (necks vary in length, but average around 6 feet or 72 inches).