It's about as long as Hadrian's Wall.
(a.k.a. Roman Wall, a.k.a. The Wall, a.k.a. Vallo di Adriano, a.k.a. Vallum Aelium, a.k.a. Severus' Wall) (from North Tyneside, Tyne and Wear, England, United Kingdom to Cumbria, North West England, United Kingdom)
It's about one-and-one-tenth times as long as The 405.
In other words, 594 furlongs is 1.0253 times the length of The 405, and the length of The 405 is 0.97532 times that amount.(a.k.a. I-405, Interstate 405, San DIego Freeway) (Southern California)
It's about one-and-one-tenth times as long as The English Channel.
In other words, 594 furlongs is 1.12 times the length of The English Channel, and the length of The English Channel is 0.893 times that amount.(average width between Isle of Ushant and The Walde Lighthouse) (La Manche, Ärmelkanal, Mor Breizh, Mor Bretannek) (a.k.a. The Channel)
The English Channel measures between 532 furlongs, narrowing as it flows northeast. The world speed record for a Channel crossing by swimmer was set by Australian Trent Grimsey in 2012, with a time of 6 hours, 55 minutes.
It's about one-and-two-fifths times as long as The Panama Canal.
In other words, the length of The Panama Canal is 0.71 times 594 furlongs.(Canal de Panamá) (Panama)
It's about one-fourth as long as The Grand Canyon.
In other words, 594 furlongs is 0.268 times the length of The Grand Canyon, and the length of The Grand Canyon is 3.73 times that amount.(a.k.a. Gran Cañón) (Arizona) (Colorado River miles measure)
It's about four-and-a-half times as tall as Olympus Mons.
In other words, the height of Olympus Mons is 0.23 times 594 furlongs.(a.k.a. Mount Olympus) (Mars)
It's about eleven times as tall as The Challenger Deep (Marianas Trench).
In other words, 594 furlongs is 10.961 times the height of The Challenger Deep (Marianas Trench), and the height of The Challenger Deep (Marianas Trench) is 0.091233 times that amount.(near Marianas Islands, a.k.a. Ladrones Islands, northwestern Pacific Ocean) (depth below sea level)