What scientific discovery or technological invention do you choose as being important?

I consider the advent of the airplane to be the most significant advancement over the past two centuries. This remarkable invention has fundamentally transformed transportation, allowing for quick and extensive journeys over long distances. Air travel has effectively made the world smaller, enabling people to travel between continents within hours instead of days or weeks. This innovation has had a significant impact on various sectors such as global trade, tourism, and cultural exchange. For instance, my cousin Andrew, who works in international trade, frequently highlights the crucial role that air travel plays in his field. Prior to the era of airplanes, transporting goods across continents was a lengthy process that could take weeks, greatly constraining the potential for business. Nowadays, the speed and efficiency of air travel allow him to manage transactions and partnerships worldwide, substantially broadening the scale and profitability of his endeavors.