State immunity — State-owned property — Shipwrecked warship and cargo — Foreign Sovereign Immunities Act 1976 — Subject-matter jurisdiction — Determination of immunity from arrest and proceedings in rem — Commercial activity exception to immunity — Whether applicable to in rem proceedings — Treatment of cargo aboard shipwreck — Federal Rules of Civil Procedure 12(b)(1) — Comity — 1902 Treaty of Friendship and General Relations between the United States of America and Spain — Relationship between domestic and international law — 1958 Geneva Convention on the High Seas

Sea — Seabed — Shipwrecks — Ownership — Shipwrecked warship — Whether in rem proceedings barred by State immunity — The law of the United States