The Great Circle

Quantifying ancient monument alignment across eight independent databases

Overview

The Great Circle program examines a long-discussed but never rigorously tested observation: that a disproportionate number of ancient monuments fall near a single great circle path first identified by Jim Alison. The corpus comprises 228,937 archaeological site records across 8 independently compiled databases, after within-database deduplication, drawn from over 640,000 raw database entries. The program applies statistical methods with land-constrained Monte Carlo baselines to distinguish genuine clustering from geographic coincidence.

Key Findings

1. Monument Enrichment: 2.52×

Monuments within 50 km of the Alison circle occur at 2.52 times the rate expected under a land-constrained null model (Z = 6.74), on the pre-2000 BCE monument subset. Per-database results vary: the enrichment is present in some source databases and absent or reversed in others, and the divergence signal is Egypt-dependent. The per-database breakdown is reported in the manuscript.

2. Settlement Anti-Clustering: Z = −2.91

Non-monumental settlements show the opposite pattern: they are significantly under-represented near the circle. The divergence between monument and settlement distributions is the key finding — it cannot be explained by geographic sampling bias.

3. Temporal Concentration

The enrichment peaks between 3000–2000 BCE, driven entirely by Egyptian Old Kingdom pyramids in the Memphis Necropolis (within 7 km of the circle). This temporal specificity is inconsistent with a uniform geographic explanation.

4. Geological Circumscription Index

Independent state-origin coordinates show non-random clustering near the corridor under a geological-tectonic circumscription model. Full statistical results and reproducible methodology are reported in the companion manuscript (Allan 2026).

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Papers & Data

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Data & Code

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