Which development most influence the spread of globalization in the 20th century?

Answer: informational revolution initiated in 1990s. It is this revolution that started a very intense globalization not only on individual level but also in terms of business and science.

Explanation: this informational revolution can be viewed as an extension of other 20th-century revolutionary events (decolonization, sexual revolution, feminist movements etc.). But it seems to be a fundamental characteristic of the 21st century. This informational revolution goes hand in hand with other revolutionary movements ... for exemple it is not national governments anymore that form and create international policy, or there is a significant economic revolution open to general migration (phenomenon that deserve attention here is a economic liberalization of China).