On 23 July 1921, the first National Congress of the Chinese Communist Party was opened secretly in a house on Huangpi Road in Shanghai. The meeting is considered as the official founding meeting of the party. Thirteen delegates were present, among them Mao Zedong, and two foreign advisors, one of them the Dutchman Henk Sneevliet (known in China by his pseudonym Maring - transcribed as Ma Lin, 马林 ).
The building became a museum, effectively a place of pilgrimage. The museum attracts hundreds of thousands of visitors annually.

Links:

Denise Y. Ho, Curating Revolution – Politics on Display in Mao’s China (Cambridge: Cambridge University Press, 2018)

Samuel Y. Liang, The Past and Present of the CCP First Congress Memorial, Shanghai (2009)

Henk Sneevliet, Mind and Heart for Revolutionary Socialism in Europe and Asia (2009)