It's about one-two-thousand-five-hundredth as tall as a Mauna Loa
In other words, 13 feet is 0.000432 times the height of a Mauna Loa, and the height of a Mauna Loa is 2,314 times that amount.(Hawaii) (Hawaiian island volcano) (total height from seafloor)
Mauna Loa, one of the five volcanoes which forms the island of Hawaii and the tallest mountain in total height in the world, rises to 30,180 feet above the seafloor. The peak of Loa is home to the approximately 6,000 sq. m (0.6 ha) Lake Waiau, one of the highest altitude lakes in the United States outside of Colorado.
It's about one-three-thousandth as deep as The Challenger Deep (Marianas Trench)
In other words, 13 feet is 0.0003635 times the depth of The Challenger Deep (Marianas Trench), and the depth of The Challenger Deep (Marianas Trench) is 2,751.3 times that amount.(near Marianas Islands, a.k.a. Ladrones Islands, northwestern Pacific Ocean) (depth below sea level)
The Challenger Deep, at the southern end of the Marianas Trench, reaches a depth of 35,768 feet below sea level. The first manned expedition to the bottom of Challenger Deep took 4 hours and 48 minutes in 1960. This was the only manned descent to the floor of the Trench until 2012, when director James Cameron made the trip; several other descents have been made since then.
It's about one-three-thousandth as tall as Maxwell Montes
In other words, 13 feet is 0.0004 times the height of Maxwell Montes, and the height of Maxwell Montes is 2,800 times that amount.(Ishtar Terra, Venus)
Maxwell Montes rises to a total height of 36,000 feet. Since Venus does not seem to have the kind of tectonic activity which gives rise to mountains on Earth, the origin of the Venusian mountain remains the subject of some dispute.
It's about 3,000 times as long as a Grain of Sand
In other words, 13 feet is 3,170 times the length of a Grain of Sand, and the length of a Grain of Sand is 0.00032 times that amount.(medium grain)
Composed mainly of quartz, mica, feldspar, or magnetite, a grain of sand measures an average of 0.0041 feet. In 2007, a team of seven in Myrtle Beach created the world's tallest sandcastle, which measured 49.50 feet in height.
It's about one-six-thousand-five-hundredth as tall as Olympus Mons
In other words, 13 feet is 0.0002 times the height of Olympus Mons, and the height of Olympus Mons is 6,700 times that amount.(a.k.a. Mount Olympus) (Mars)
The tallest mountain in the solar system, Olympus Mons rises to approximately 89,000 feet. The mountain has been known to astronomers since the nineteenth century because it is tall enough to rise above Mars' frequent dust storms.
It's about one-twenty-thousandth as long as The Panama Canal
In other words, 13 feet is 0.000045 times the length of The Panama Canal, and the length of The Panama Canal is 22,000 times that amount.(Canal de Panamá) (Panama)
Connecting the Atlantic and Pacific Oceans across the Isthmus of Panama, the Canal measures 290,000 feet in length. Ships passing through the Canal are raised (and then lowered) 85 feet above sea level through the lock-and-dam system.
It's about one-twenty-five-thousandth as wide as The English Channel
In other words, 13 feet is 0.000037 times the width of The English Channel, and the width of The English Channel is 27,000 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 351,000 feet, 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.