Eurodollars (interest rate) are by at least one magnitude the most liquid futures market in the world. The Eurodollar market was one of my favorite markets to trade prior to the insane QE-infinity of the world's central bankers. It is insane how liquid Euros are -- typical monthly volume will exceeds 40 million contracts. Unlike most futures markets wherein the liquidity resides in the nearest contract, Euro contracts are liquid for several years into the future.