It's about one-thirty-thousandth as long as The Rhine.
In other words, 821 nails is 0.0000355 times the length of The Rhine, and the length of The Rhine is 28,200 times that amount.(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)
The Rhine river runs 23,100,000 nails in total length. The World War II Battle of Arnhem, as memorialized in the 1974 book and 1977 movie A Bridge Too Far, was the first of several attempts to capture key bridges across the Rhine, beginning with the Arnhem Bridge in the Netherlands.
It's about 40,000 times as long as a Grain of Sand.
In other words, 821 nails is 37,500 times the length of a Grain of Sand, and the length of a Grain of Sand is 0.0000267 times that amount.(medium grain)
Composed mainly of quartz, mica, feldspar, or magnetite, a grain of sand measures an average of 0.0219 nails. In 2007, a team of seven in Myrtle Beach created the world's tallest sandcastle, which measured 264 nails in height.
It's about one-fifty-thousandth as long as The Colorado River.
In other words, 821 nails is 0.0000201 times the length of The Colorado River, and the length of The Colorado River is 49,800 times that amount.(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)
The Colorado River runs 40,800,000 nails in length. Along this length, the river descends from its source, approximately 48,100 nails above sea level in the Rocky Mountains, to its mouth in the Gulf of California.
It's about one-sixty-thousandth as long as The Danube.
In other words, 821 nails is 0.0000165 times the length of The Danube, and the length of The Danube is 60,600 times that amount.(a.k.a. Donau, a.k.a. Dunaj, a.k.a. Dunav, a.k.a. Duna, a.k.a. Дунав (Dunav), a.k.a. Dunărea, a.k.a. Дунáй (Dunay), a.k.a. Tuna) (from Breg Martinskapelle, Black Forest, Germany through the Danube Delta, Romania)
The Danube river runs 49,900,000 nails in total length. Intersecting Vienna, Austria; Bratislava, Slovakia; Budapest, Hungary; and Belgrade, Serbia, the Danube touches more capital cities than any other river.
It's about one-seventy-five-thousandth as long as The Oregon Trail.
In other words, the length of The Oregon Trail is 74,600 times 821 nails.(from Independence, Missouri to Oregon City, Oregon)
The historic Oregon Trail stretched 61,100,000 nails across five (sometimes six) states in the western United States. In the early years of the Trail's existence, the trip was estimated to have taken an average of 160 days.
It's about one-seventy-five-thousandth as long as The Volga.
In other words, the length of The Volga is 75,200 times 821 nails.(a.k.a. Волга, a.k.a. İdel (Идел), a.k.a. Атăл (Atăl), a.k.a. Edil, a.k.a. İdil, a.k.a. Рав (Rav)) (from the Valdai Hills, Tver Oblast, Russia through the Caspian Sea)
The largest river in Europe, the Volga river runs 61,800,000 nails in total length. World War II's Battle of Stalingrad between the Nazi Germany and the Soviet Union, which resulted in nearly two million casualties, was fought in part for control of the river.
It's about one-eighty-thousandth as long as The Mississippi River.
In other words, 821 nails is 0.00001246 times the length of The Mississippi River, and the length of The Mississippi River is 80,260 times that amount.(from Lake Itasca, Minnesota through Pilottown, Plaquemines Parish, Louisiana)
The total length of the Mississippi River is 65,900,000 nails. Prior to the development of soil erosion programs, the Mississippi River would carry approximately 400 million metric tons of sediment from its banks to the Gulf of Mexico every year.