Containers are standardized, reusable cargo units designed for the efficient transport of goods across multiple modes, including ships, trucks, and trains. Typically made of steel or aluminum, they come in various sizes, with the 20-foot and 40-foot variants being most common. Containers revolutionized global trade by streamlining loading and unloading processes, reducing costs, and enabling intermodal transport. They play a critical role in supply chains and international commerce.