Editor's Note: November 9 marked the 30th anniversary of the fall of the Berlin Wall, which had not only divided the Federal Republic of Germany and the German Democratic Republic, but also divided the East and West during the Cold War. Its fall symbolized the end of the Cold War. Beijing Youth Daily comments:

While looking back at this historic moment, people should focus more attention on the new phenomenon that some invisible or tangible walls are being built.

In Germany itself, the development gap between the east and the west is still evident, and the development in the east has seemingly come to a standstill, with only 7 percent of Germany's 500 most valuable companies based in the east. In other words, there is still an invisible wall of social and economic development within Germany.

From a global perspective, the Cold War, of which the Berlin Wall was a tangible symbol, was a misfortune for all mankind, given that the ideological divide between countries led to mutual estrangement, tension, and even hot wars. After the end of the Cold War, the world ushered in a new period of cooperation and opportunity as highlighted by the trend of globalization.

Yet 30 years after the end of the Cold War, some forces and individuals still have a Cold War mentality and wear colored glasses, criticizing different social systems and development models and promoting "color revolutions" in an attempt to curb the rise and development of countries with different ideologies. For example, in a recent speech in Berlin, US Secretary of State Mike Pompeo lashed out at China, displaying his outdated Cold War thinking and zero-sum game mentality.

Multilateralism, globalization and regional integration that were booming after the end of the Cold War are now encountering headwinds with the United States withdrawing from multilateral treaties and mechanisms like the Paris Agreement on climate change.

The lessons of history tell us that the more difficult our time is, the more we need to work together. No country alone can address the emerging difficulties facing globalization, or climate change, terrorism, migration and other challenges.

For countries to join hands instead of letting go, it is necessary for them to reject any bid to build only walls between them.