Euro versus US dollar — about 24% of all forex volume passes through here.
The deepest, tightest pair in forex. Driven by the ECB-Fed rate differential, eurozone PMI/IFO data, and US payrolls/CPI.
Two of the world's largest economies on either side. Round-the-clock interbank flow keeps spreads ultra-tight.
London-NY overlap (13:00–17:00 GMT) — biggest moves, best liquidity.
60–100 pips on a normal day; 150–250 on big data days (NFP, FOMC, ECB).