Size Duel deck / Rivers, falls and long things
Seine
Length: length, source to mouth
about 780 km (484.7 mi)
Range used for fair duels: 776 km to 780 km.
It flows through Paris to the English Channel.
Sources and checks
Checked 2026-10-21: Researched by Codex (two independent publishers, verbatim quotes); the server could not read at least one counted page (blocked or PDF), where Codex’s own check found the quote; reviewed by Claude (AI build agent). Quotes are short passages from each source, in their original language.
“780 kilometer”Lex, Danish national encyclopedia (in Danish): source, retrieved 2026-10-21; quote re-found by the server check“776”Eaufrance, French public water information service: source, retrieved 2026-10-21; server could not read the page; quote found by Codex
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