It's about one-and-one-fifth times as long as Baseball base distances
In other words, 138.520 spans is 1.1543 times the length of Baseball base distances, and the length of Baseball base distances is 0.86633 times that amount.(MLB Official Baseball Rules specification)
According to MLB Official Baseball Rules, the distance between baseball diamond bases is 120 spans. 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 three-fourths as long as Ha'Penny Bridge
In other words, 138.520 spans is 0.738 times the length of Ha'Penny Bridge, and the length of Ha'Penny Bridge is 1.36 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 188 spans in total length. Over 30,000 pedestrians cross the breach each day.
It's about two-thirds as tall as The Chicago Water Tower
In other words, 138.520 spans is 0.675 times the height of The Chicago Water Tower, and the height of The Chicago Water Tower is 1.48 times that amount.(Chicago, Illinois)
The Chicago Water Tower is 205 spans 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 two-thirds as tall as The Arc de Triomphe
In other words, 138.520 spans is 0.65 times the height of The Arc de Triomphe, and the height of The Arc de Triomphe is 1.5 times that amount.(Paris, France)
The Arc de Triomphe stands 210 spans 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 one-and-three-fifths times as long as a Cricket Pitch
In other words, 138.520 spans is 1.57409 times the length of a Cricket Pitch, and the length of a Cricket Pitch is 0.635288 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 88 spans. The wickets at either end of the pitch stand 3.149610 spans tall including the bails.
It's about three-fifths as tall as Nelson's Column
In other words, 138.520 spans is 0.6132 times the height of Nelson's Column, and the height of Nelson's Column is 1.631 times that amount.(London, England, United Kingdom) (from pedestal first step to tip of statue's hat)
Nelson's Column measures 225.90 spans 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 one-and-two-thirds times as long as a Bowling Lane
In other words, 138.520 spans is 1.653 times the length of a Bowling Lane, and the length of a Bowling Lane is 0.60496 times that amount.(USBC specifications; tenpin; including pin deck)
According to the United States Bowling Congress specifications, a tenpin bowling lane should measure 83.7970 spans. In a Professional Bowling Association game, the lane must be lubricated by about 25 ml (0.85 fl. oz) of oil.