How long is 13 feet?
It's about one-two-thousand-five-hundredth as tall as a Mauna Loa

The height of a Mauna Loa is about 30,080 feet.
(Hawaii) (Hawaiian island volcano) (total height from seafloor)
It's about one-three-thousandth as deep as The Challenger Deep (Marianas Trench)
The depth of The Challenger Deep (Marianas Trench) is about 35,768 feet.
(near Marianas Islands, a.k.a. Ladrones Islands, northwestern Pacific Ocean) (depth below sea level)
It's about one-three-thousandth as tall as Maxwell Montes
The height of Maxwell Montes is about 36,000 feet.
(Ishtar Terra, Venus)
It's about 3,000 times as long as a Grain of Sand
The length of a Grain of Sand is about 0.0041 feet.
(medium grain)
It's about one-six-thousand-five-hundredth as tall as Olympus Mons
The height of Olympus Mons is about 89,000 feet.
(a.k.a. Mount Olympus) (Mars)
It's about one-twenty-thousandth as long as The Panama Canal

The length of The Panama Canal is about 290,000 feet.
(Canal de Panamá) (Panama)
It's about one-twenty-five-thousandth as wide as The English Channel
The width of The English Channel is about 351,000 feet.
(average width between Isle of Ushant and The Walde Lighthouse) (La Manche, Ärmelkanal, Mor Breizh, Mor Bretannek) (a.k.a. The Channel)
It's about one-thirty-thousandth as long as The 405

The length of The 405 is about 382,350 feet.
(a.k.a. I-405, Interstate 405, San DIego Freeway) (Southern California)
It's about one-thirty-thousandth as long as Hadrian's Wall

The length of Hadrian's Wall is about 390,000 feet.
(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 40,000 times as wide as a Strand of Hair
The width of a Strand of Hair is about 0.00032 feet.
(average)
It's about 40,000 times as tall as a sheet of Paper
The height of a sheet of Paper is about 0.0003 feet.
(for US Letter, a.k.a. ANSI A; 215.9mm by 279.4mm (8.5 in x 11 in); 20lb)
It's about one-one-hundred-thousandth as long as The Grand Canyon

The length of The Grand Canyon is about 1,460,000 feet.
(a.k.a. Gran Cañón) (Arizona) (Colorado River miles measure)
It's about one-three-hundred-fifty-thousandth as long as The Rhine
The length of The Rhine is about 4,330,000 feet.
(a.k.a. Rhein, a.k.a. Rijn, a.k.a. Rhin, a.k.a. Rain, a.k.a. Reno, a.k.a. Rhenus, a.k.a. Ryn) (from near Reichenau, Switzerland through Hoek van Holland, Rotterdam, Netherlands)
It's about 550,000 times as long as a Red Blood Cell
The length of a Red Blood Cell is about 0.0000250 feet.
(a.k.a. RBCs, a.k.a. haematids, a.k.a. erythrocyte, a.k.a. erythroid cells, a.k.a. red blood corpuscles)
It's about one-six-hundred-thousandth as long as The Colorado River

The length of The Colorado River is about 7,640,000 feet.
(a.k.a. Aha Kwahwat, a.k.a. Grand River, a.k.a. Tizon River, a.k.a. Tecon River, a.k.a. Tison River) (from Grand Lake, Colorado through the Gulf of California)