Many people in Bulgaria's capital, Sofia, know about an ancient building on Oborishte Street - the former home of Dr Ianto Kaneti (1910-2004) and his Chinese wife, Zhang Sunfen.
The couple's lives are revealed in the documentary serial The Journey of Danube airing on Guangdong TV.
The 80-episode series features the lives of those living in the countries through which the Danube River flows, focusing on their relationships with China. It touches on these countries' culture, history, people, music, towns and cities, economy and society.
The Journey of Danube is co-produced by Guangdong International Culture Association, Southern Media Corporation and Guangdong TV, among other domestic organizations.
The story of Kaneti and Zhang demonstrates the friendship between Bulgaria and China.
After graduating from Yenching University in 1940, Zhang joined the Chinese War of Resistance against Japanese Aggression (1937-1945). She went to Guiyang, Guizhou province, in 1943, where she met Bulgarian Kaneti, who was among the 17 doctors from the Fascist-occupied countries selected to join a medical team to aid China.
Zhang and Kaneti fell in love and moved to Bulgaria in 1945.
The couple made great contributions to building up the two countries' relationship. Zhang quit her hospital job and worked as a translator in the Chinese embassy. In 1952, she helped build a Chinese school in Bulgaria with professors from her homeland.
In 2007, the documentary's production team visited her apartment in Sofia city.
The team worked in nine other countries over three years. These include Germany, Austria, Hungary, Slovak, Croatia, Serbia, Romania, Moldova and Ukraine. They traveled more than 10,000 kilometers and interviewed more than 100 experts, celebrities and diplomats from home and abroad.
The final product has been airing on Guangdong TV's Guangdong News Channel for the past four months, to great acclaim. Its broadcast is also a celebration of the 35th anniversary of the establishment of diplomatic relations between China and Europe.
The English version has been showing on the International Channel Shanghai since June 27, and it will air in Europe and South America in the coming months.
German Ambassador Michael Schaefer says more Chinese people can see what the Danube looks like from the documentary, explaining that those sceneries are "part of our soul".
Hungarian Ambassador Sandor Kusai says: "I think this documentary shall not be underestimated. It provides much knowledge for Chinese people and lets us all know how important it is that we should cooperate."
A National Radio & Film Symphony Orchestra concert, promoting the documentary and showcasing Danube countries' music, has been staged in Guangzhou and will tour Beijing's Poly Theater on Aug 24.