It's about 65,000 times as tall as Nelson's Column
In other words, 623 leagues is 67,030 times the height of Nelson's Column, and the height of Nelson's Column is 0.00001492 times that amount.(London, England, United Kingdom) (from pedestal first step to tip of statue's hat)
Nelson's Column measures 0.009294 leagues from the first step of the pedestal's base to the top of the statue's hat. While the London tower is the tallest, there are at least eight other monuments to Admiral Horatio Nelson, 1st Viscount Nelson, 1st Duke of Bronté throughout England, Scotland, Ireland, Canada, and Barbados.
It's about 70,000 times as tall as The Arc de Triomphe
In other words, 623 leagues is 71,000 times the height of The Arc de Triomphe, and the height of The Arc de Triomphe is 0.000014 times that amount.(Paris, France)
The Arc de Triomphe stands 0.0088 leagues tall. France's Tomb of the Unknown Soldier from the First World War lies beneath the arch and is commemorated by the first eternal flame to have been lit in modern European history.
It's about 75,000 times as tall as The Chicago Water Tower
In other words, 623 leagues is 73,800 times the height of The Chicago Water Tower, and the height of The Chicago Water Tower is 0.0000136 times that amount.(Chicago, Illinois)
The Chicago Water Tower is 0.00844 leagues 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 80,000 times as long as Ha'Penny Bridge
In other words, 623 leagues is 80,700 times the length of Ha'Penny Bridge, and the length of Ha'Penny Bridge is 0.0000124 times that amount.(a.k.a. Droichead na Leathphingine, a.k.a. Liffey Bridge, a.k.a. Droichead na Life, f.k.a. Wellington Bridge) (Quay of Bachelors Walk, Temple Bar Neighborhood, Dublin, Ireland)
The Ha'Penny Bridge, crossing the River Liffey in Dublin, measures 0.00772 leagues in total length. Over 30,000 pedestrians cross the breach each day.
It's about 150,000 times as long as Baseball base distances
In other words, 623 leagues is 126,180 times the length of Baseball base distances, and the length of Baseball base distances is 0.0000079252 times that amount.(MLB Official Baseball Rules specification)
According to MLB Official Baseball Rules, the distance between baseball diamond bases is 0.0049374 leagues. 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 150,000 times as long as a Cricket Pitch
In other words, 623 leagues is 172,065 times the length of a Cricket Pitch, and the length of a Cricket Pitch is 0.00000581176 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 0.00362073 leagues. The wickets at either end of the pitch stand 0.00012959 leagues tall including the bails.
It's about 200,000 times as long as a Bowling Lane
In other words, 623 leagues is 180,690 times the length of a Bowling Lane, and the length of a Bowling Lane is 0.0000055343 times that amount.(USBC specifications; tenpin; including pin deck)
According to the United States Bowling Congress specifications, a tenpin bowling lane should measure 0.0034478 leagues. In a Professional Bowling Association game, the lane must be lubricated by about 25 ml (0.85 fl. oz) of oil.