It's about 15,000 times as tall as The Chicago Water Tower.
In other words, 668 kilometers is 14,200 times the height of The Chicago Water Tower, and the height of The Chicago Water Tower is 0.00007040 times that amount.(Chicago, Illinois)
The Chicago Water Tower is 0.0469 kilometers tall. The tower's architecture was one source of inspiration behind the design of White Castle fast-food restaurants beginning with "Building Number 8," a prefabricated structure built in Minneapolis, Minnesota in 1936.
It's about 25,000 times as long as Baseball base distances.
In other words, 668 kilometers is 24,351 times the length of Baseball base distances, and the length of Baseball base distances is 0.0000410660 times that amount.(MLB Official Baseball Rules specification)
According to MLB Official Baseball Rules, the distance between baseball diamond bases is 0.027432 kilometers. While second and home base are located upon the corners of the 27.432 sq. m area created by the bases, first and third base are placed within that square, to better allow the umpires to judge whether a ball is fair or foul.
It's about 35,000 times as long as a Cricket Pitch.
In other words, 668 kilometers is 33,206.10 times the length of a Cricket Pitch, and the length of a Cricket Pitch is 0.00003011490 times that amount.(per Marylebone Cricket Council / International Cricket Council Law #6)
The length of a cricket pitch, from one bowling crease to the other, is 0.0201168 kilometers. The wickets at either end of the pitch stand 0.00072 kilometers tall including the bails.
It's about 35,000 times as long as a Bowling Lane.
In other words, 668 kilometers is 34,872 times the length of a Bowling Lane, and the length of a Bowling Lane is 0.0000286760 times that amount.(USBC specifications; tenpin; including pin deck)
According to the United States Bowling Congress specifications, a tenpin bowling lane should measure 0.019156 kilometers. In a Professional Bowling Association game, the lane must be lubricated by about 25 ml (0.85 fl. oz) of oil.
It's about 45,000 times as tall as The Hollywood Sign.
In other words, the height of The Hollywood Sign is 0.0000220 times 668 kilometers.(a.k.a. Hollywoodland Sign) (Mount Lee, Hollywood Hills, Santa Monica Mountains, California)
Each of the white letters in the Hollywood Sign measures 0.015 kilometers tall. Built as an advertisement in 1923, the sign was intended to stand for only eighteen months.
It's about 45,000 times as long as a Semitrailer.
In other words, 668 kilometers is 45,660 times the length of a Semitrailer, and the length of a Semitrailer is 0.00002190 times that amount.(a.k.a. semi-trailer truck, a.k.a. semi, a.k.a. tractor-trailer, a.k.a. truck and trailer, a.k.a. eighteen-wheeler, a.k.a. big rig, a.k.a. Mack truck, a.k.a. transport, a.k.a. lorry, a.k.a. artic; for box truck; United States Federal length limits)
According to the United States Department of Transportation (DOT), the maximum allowable length of a semitrailer pulled by a road tractor truck is 0.01463 kilometers (unless superseded by state law). These regulations also allow the vehicles to tow up to 36,000 kg in gross weight.
It's about 50,000 times as tall as a Brachiosaurus.
In other words, the height of a Brachiosaurus is 0.0000200 times 668 kilometers.(based on comparable bone measurements, height to head)
Dinosaurs in the genus Brachiosaurus had an estimated height (at the head with neck fully extended) of up to 0.013 kilometers. A resin cast of the first Brachiosaurus specimen, owned by the Field Museum in Chicago, is currently on display at the O'Hare International Airport.