Final answer:
The EU lowered trade barriers among its members, fostering integration and introducing the euro, although Britain's exit (Brexit) marked a deviation from this trend.
Step-by-step explanation:
The European Union (EU) aimed to lower trade barriers for its member countries when it became an economic union. Following World War II, European leaders began efforts to bind their economies more closely to avoid conflict. Initially starting as a free trade association, it evolved into a common market and finally into a comprehensive economic union. The introduction of the euro as a common currency and the elimination of barriers to the free movement of goods, labor, and capital are among the pivotal achievements of the EU.
In recent decades, the general trend has been towards lower trade barriers. The EU's efforts have significantly contributed to this trend, facilitating easier trade, work, and investment across member states, although the move known as Brexit in 2016, where Britain voted to leave the EU, was a notable exception to this trend.