On Wednesday, both Chinese President Hu Jintao and US President Barack Obama recalled in their speeches the days when China and the United States broke off their estrangement and started to engage in exchanges and improve mutual understanding despite their differences in ideology and social systems.

While Obama quoted late Chinese leader Deng Xiaoping's comment that there are still great possibilities for cooperation between the two countries, Hu went back 40 years to recollect how former US president Richard Nixon, along with his then national security advisor Henry Kissinger, made the ice-breaking visit and started a relationship that has changed the world.

Since then, China-US relations have weathered many trials and tribulations with seven US presidents and four generations of Chinese leadership.