We have some very specific obsessions. One of them? Stories about museums that end up in possession of objects that are so big and heavy that curators literally don't know how to display them without causing the museum's floors to collapse. Below, we've collected five of the most gigantic things on display (or not on display, as the case may be) in museums around the world. For comparison's sake, we've translated each objects weight into full-grown African bush elephants, which each weigh about 6.5 tons. Unlike elephants, the massive objects below can't move on their own. So how did they end up in some of the world's finest museums? A whole lot of manpower, time, and cold, hard cash.

5. Sarcophagus of King Aspelta: 2 elephants

Visitors to Boston's Museum of Fine Arts have a huge selection of ancient Egyptian and Nubian artifacts to marvel at—but one of the museum's most spectacular pieces isn't on display because, at 16 tons, it's simply too heavy. Made in the 6th century B.C.E. out of solid granite, the sarcophagus of Nubian king Aspelta was found in the early 20th century in modern-day Sudan. It was given to the MFA in 1923, but because none of the museum's floors were strong enough to hold it, it's been relegated to the basement ever since.

4. Winged Bulls from Khorsabad: 2 elephants each

via Flickr user averain

Each of the British Museum's two massive statues of winged, human-headed bulls (or lamassus) from Khorsabad weighs about 16 tons, each was sawed into several smaller pieces, and then reassembled in London. The British Museum's two similar statues from Nimrud were a bit easier to transport at a mere 10 tons each. For those, wheeled carts pulled by 300 men apiece sufficed.

3. Aztec Calendar Stone: 3 full-grown elephants and a baby elephant

Believed to date to the 16th century, this massive basalt sculpture—also known as the Sun Stone—was buried underneath the plot of land that became Mexico City's Zócalo (or central square) shortly after the Spanish conquest of the region. With a diameter of 11 feet and a weight of 24 tons, it's pretty hard for visitors of Mexico City's National Anthropology Museum to miss.

2. Cape York/Ahnighito meteorite, American Museum of Natural History, New York: 5 elephants

The Cape York Ahnighito Meteorite was recovered in Greenland by famous American Navy Arctic explorer Robert E. Peary, with the help of a local Inuit guide, in 1894. Hauling it to the AMNH turned out to be a pretty insane undertaking. The 4.5-billion-year-old, 34-ton meteorite was so heavy that Peary had to build a tiny railroad just to get it to the ship. The meteorite almost fell into the water when waves from an ill-timed iceberg avalanche crashed into the ship, but they eventually got it to the Brooklyn Navy Yard. It took 80 horses to haul the meteorite to the front door of the AMNH. Once there, the threat of the museum's floors collapsing due to Ahnighito's enormous girth was so great that a special display was built for it on the museum's lowest level, with supports that reach down into the bedrock below.

1. Levitated Mass: 52 elephants

via Flickr user m-bot

Artist Michael Heizer made headlines in 2011 when he arranged to move a 340-ton boulder from California's Jurupa Valley to the Los Angeles County Museum of Art. The 11-day, 106-mile trip cost an estimated $10 million, and attracted hundreds of onlookers. When it finally reached Los Angeles, the monolith was placed over a specially-built passageway that allows visitors to walk underneath and marvel at its size. Was it worth the time, expense, and manpower? Los Angeles Times art critic Christopher Knight called it "a good sculpture if not a great one," and went on to write, "'Levitated Mass' isn't exactly Stonehenge or Half Dome. It's not even Eagle Rock. As monoliths go, the stone seems rather modest."