It's about six-and-a-half times as tall as The Great Pyramid of Giza
In other words, the height of The Great Pyramid of Giza is 0.160 times 30 shackles.(a.k.a. Pyramid of Khufu, a.k.a. Pyramid of Cheops) (Cairo, Egypt) (estimated original height)
The Great Pyramid of Giza has an estimated original height (without loss due to erosion) of 4.70 shackles. The Pyramid was the tallest structure in the world for almost 4,000 years — from its construction ca. 2551 BCE until it was overtaken by the Lincoln Cathedral in Lincoln, England, built in the year 1300.
It's about one-tenth as tall as Mount Elbrus
In other words, 30 shackles is 0.14590 times the height of Mount Elbrus, and the height of Mount Elbrus is 6.8540 times that amount.(a.k.a. Mingi Tau, a.k.a. Эльбрус, a.k.a. იალბუზი) (Karachay-Cherkessia and Kabardino-Balkaria, Russia) (west summit)
The west summit of the dual-summit volcano Mount Elbrus is 205.70 shackles at its peak and is the highest peak in both Russia and the European continent. Until 1976, a cable car would take visitors to the mountain as far up as the Garabashi camp, located at an elevation of 138.50 shackles.
It's about one-tenth as tall as a Kilimanjaro
In other words, 30 shackles is 0.1397030 times the height of a Kilimanjaro, and the height of a Kilimanjaro is 7.158040 times that amount.(a.k.a. Mount Kilimanjaro) (Tanzania) (to Uhuru peak; 2008 gravimeter measurement)
Kilimanjaro rises to 214.7420 shackles at its peak. An isolated peak with no surrounding mountain range, Kilimanjaro is considered the world's tallest freestanding mountain.
It's about one-tenth as tall as Mount Logan
In other words, 30 shackles is 0.13810 times the height of Mount Logan, and the height of Mount Logan is 7.2410 times that amount.(Kluane National Park and Reserve, Yukon, Canada) (elevation)
The highest mountain in Canada, Mount Logan has a total height of 217.30 shackles. The high altitude and northern latitude of the mountain resulted in one-time temperature of -77.5 °C — the lowest temperature ever recorded outside of Antarctica.
It's about seven-and-a-half times as long as a Football field
In other words, the length of a Football field is 0.1333330 times 30 shackles.(American) (total distance; per NFL regulation)
According to NFL specifications, an American football field should measure 4 shackles from end to end. Because each team's goalpost is located at the far end of the scoring area (end zone), a ball on a scoring play may need to travel as many as 0.3333330 shackles farther when kicked into the scoring area than when run (rushed) or passed into it.
It's about one-tenth as tall as Denali
In other words, 30 shackles is 0.13290 times the height of Denali, and the height of Denali is 7.5240 times that amount.(a.k.a. Mount McKinley, a.k.a. Doleika, a.k.a. Traleika, a.k.a. "The Great One") (Denali National Park and Preserve, Alaska) (South peak)
The highest mountain peak in North America, Denali's South Peak measures 225.80 shackles above sea level at its peak. The impetus for the name Mount McKinley was US president William McKinley of Ohio, and disputes over the which of the mountain's names should be officially recognized regularly occur between Ohio Congressmen and Alaska politicians.
It's about eight times as long as a Football (Soccer) Pitch
In other words, 30 shackles is 7.840 times the length of a Football (Soccer) Pitch, and the length of a Football (Soccer) Pitch is 0.1280 times that amount.(a.k.a. Football Field, a.k.a. Soccer Field) (field length, a.k.a. touchline distance)
According to the Laws of the Game, a football pitch should measure between 3.830 shackles (when the Laws were originally, they used imperial measurements of 3.830 shackles, and later converted to the metric units used today). The goal markess were defined as part of the pitch by the original rules of the game in the late 16th century, but it was not until the mid 19th century that the crossbar and the net were added