Red tourism sites have attracted more visitors in recent years and are receiving huge investment from the country.

China's National Development and Reform Commission has encouraged more efforts to preserve revolutionary sites and released a list of red tourism sites in 2015.

In 2016, a total of 1.55 billion yuan (about $228.3 million) was spent to support "red tourism," according to the Ministry of Finance.

At another revolutionary site, Xibaipo, in Pingshan County of north China's Hebei Province, Duan Keqian, a tour guide of the Xibaipo Memorial Hall, was busy preparing an English version of her speech.

Xibaipo is an old revolutionary base where the leadership of the CPC was garrisoned from May 1948 till early 1949, drawing up the blueprint for a new country and preparing for the CPC's new role as the ruling party.

"We have been really busy in the last month, but are happy to introduce more information to our audience," said Duan, adding that she has witnessed a growing number of visiting foreign teachers, doctors and business people who work near Xibaipo.

"We have taken exams to qualify as guides. Each of us should focus on a certain field, and I focus on people's daily lives," Duan said. "People will be fired if they get poor regular assessments."

According to Duan, there are about 80 such guides at the memorial hall, as well as at the revolutionists' former residences, working in Chinese, English, Russian, Italian and Japanese languages.

Russian Andrey Lyakh, 45, visited Xibaipo after doing business in Shijiazhuang, capital of Hebei Province, about a two-hour drive away.

He listened carefully to his interpreter and nodded at times, walking in the yard of the former residences.

"I have heard of Lenin and Mao Zedong since I was a child, and I think they are all great men," said Lyakh. "The site impressed me very much."