Globalization is a complex process that involves the integration of economies, societies and cultures through communication and transportation networks. It can refer specifically to economic integration through trade and financial flows, but also involves the spread of ideas, technologies and cultural practices. While globalization has been occurring for millennia through trade and exploration, it accelerated in the late 20th century due to reductions in trade barriers and advances in transportation and communication technologies. There are ongoing debates around both the positive and negative impacts of globalization.