Eleven long-distance trade corridors from roughly 300 BCE to today, mapped between benchmark endpoints and normalized to metric tonnes per year where a defensible figure exists. Nine of the eleven carry a tonnes/year value; six of those are estimates or unit conversions and three are direct annual observations. Two stay blank by design: the Silk Roads, and the transatlantic slave trade, whose victims are never expressed as cargo mass.
Every tonnes/year figure is a single commodity- and benchmark-specific snapshot, not a continuous historical series: the animation shows when a route emerged and its relative benchmark magnitude, never year-by-year measured volume. Timeline runs 3× slower per year from the 15th century onward, so modern routes get room to breathe. Arcs are great circles between benchmark endpoints; a faded arc means the route's era has passed at the selected year.
| Route | Active | Tonnes/year | Status | Benchmark | Conversion method | Source |
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Method: 11 mapped trade corridors, one row each, normalized to metric tonnes/year; 9 rows carry a tonnes/year value, 6 of which are estimates or unit conversions (marked EST.) and 3 direct annual observations; research current to the 2023–2025 benchmark years cited per row. Each figure is a commodity- and benchmark-specific snapshot, not a time series. Arc width uses a capped logarithmic scale with a minimum visible stroke so ancient low-volume routes stay legible beside billion-tonne modern flows; the two routes without tonnage are drawn as thin dashed arcs and never plotted as zero. Timeline animation uses a piecewise mapping: each year from the 15th century onward consumes 3× the screen time of earlier years. Arcs are endpoint great circles, not exact historical paths; way stations are listed in tooltips.