Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
70
people
How to estimate it
Fermi’s official “Napkin math”
Stonehenge is smaller than most people picture. The ring of big stones is a bit wider than a tennis court is long, call it 30 meters. How much of the ring does each person cover? Arms out, about their own height, so 1.5 meters once hands overlap.
- Across the ring
- ≈ 30 m
- Around it, × 3
- ≈ 90 m
- 90 ÷ 1.5 m
- ≈ 60 people
Stonehenge is smaller than most people picture. The ring of big stones is a bit wider than a tennis court is long, call it 100 feet. How much of the ring does each person cover? Arms out, about their own height, so 5 feet once hands overlap.
- Across the ring
- ≈ 100 ft
- Around it, × 3
- ≈ 300 ft
- 300 ÷ 5 ft
- ≈ 60 people
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- Sarsen circle diameter (English Heritage)
- 30 m
- Standing just outside stones about 1 m thick
- ≈ 33 m across
- Around it, 33 × π
- ≈ 104 m
- 104 ÷ 1.5 m of line per person, hand to hand
- ≈ 70 people
Reference cited by Fermi: English Heritage: Stonehenge's sarsen circle is 30 m across. 1.5 m of line per person hand to hand is our estimate
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