Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
19,800
Hafþórs
How to estimate it
Fermi’s official “Napkin math”
Imagine melting the whole tower into a flat slab of iron on the square between its legs, about 100 meters across. How thick would it be? It's mostly air, so thinner than you'd think. Maybe 10 centimeters.
- Slab, 100 × 100 × 0.1 m
- ≈ 1,000 m³
- Iron, 8 t per m³
- ≈ 8,000 t
- One Hafþór lifts
- ≈ 500 kg
- 8,000,000 kg ÷ 500 kg
- ≈ 16,000
Imagine melting the whole tower into a flat slab of iron on the square between its legs, about 400 feet across. How thick would it be? It's mostly air, so thinner than you'd think. Maybe 4 inches.
- Slab, 400 × 400 × ⅓ ft
- ≈ 50,000 ft³
- Iron, 500 lb per ft³
- ≈ 25,000,000 lb
- One Hafþór lifts
- ≈ 1,000 lb
- 25,000,000 lb ÷ 1,000 lb
- ≈ 25,000
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Total weight of the Eiffel Tower (official site)
- 10,100 tonnes = 10,100,000 kg
- Hafþór Björnsson's best deadlift (Guinness World Records, Sept 2025)
- 510 kg (1,124 lb)
- 10,100,000 ÷ 510
- ≈ 19,800
Reference cited by Fermi: Official Eiffel Tower website (SETE), key figures · Guinness World Records, heaviest deadlift (2025)
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