Drawn by its Communist past and a visa-free regime, Chinese tourists are flocking to Russia in droves as it develops new routes touting "red tourism".

Nearly 410,000 Chinese came to Russia last year putting them on top of the list of foreign tourists, according to the federal tourism agency.

Their number has swelled 10 percent since 2013, when Germans topped the list of overseas visitors.

"We had lots of work this summer," said Viktoria Borgacheva, the head of the association of Chinese interpreters and guides in the city of Saint Petersburg, Russia's main tourist destination.

"I would say our workload has increased 30 percent since last year," Borgacheva said.

In the first half of this year alone, more than 200,000 Chinese tourists visited Russia.

Russia's second city of Saint Petersburg, the former imperial capital renowned for its world-class museums and luxurious palaces, hosted nearly 26,000 Chinese tourists in 2014.

"Saint Petersburg is a beautiful city with a rich history," said Yong Tang, a 57-year-old tourist from Beijing, as he purchased a bust of Lenin.

"I'm glad I came here."

Experts estimate that between 40,000 and 50,000 Chinese tourists could visit Saint Petersburg this year, the Russian tourism industry union said.

But Saint Petersburg's European flair and its winding canals are not the main attraction for them, according to Russian tourism officials.

Chinese tourists flock to Saint Petersburg chiefly to soak in the city's turbulent revolutionary history as the scene of three revolutions -- one in 1905 and two in 1917 -- that precipitated the end of the tsarist era and ushered in the Soviet Union.

"While Europeans come to Saint Petersburg above all to admire the old capital and the Hermitage (art museum), Chinese tourists want to see Leningrad and its revolutionary history," Borgacheva said, referring to Saint Petersburg's Soviet-era name.

-'Red circuit'-

In July Moscow and Beijing officially launched an ambitious "red circuit," a tourist route tracing the life of Bolshevik leader Vladimir Lenin in four Russian cities.

The eight-day journey starts in Moscow, where tourists can gape at hammers and sickles on Soviet-era buildings and in the sprawling metro network.

The Russian capital is also the resting place of Lenin, with his body still preserved in a mausoleum on Red Square.

The circuit then takes tourists to Lenin's birthplace of Ulyanovsk on the banks of the Volga River, before continuing to Kazan, the city where he studied.

The tour ends in Saint Petersburg, the scene of the Bolshevik revolution of 1917.

"Revolution and the people's fight for independence and even the Great Patriotic War (World War II as fought by the Soviets from 1941) are important themes for the Chinese, just as they are for us," said Sergei Lakovsky, the head of Ulyanovsk's tourist department.

Costing $1,000 per person excluding flights, the "red circuit" promises to be lucrative for the dozen Russian tourist agencies participating in the programme, expected to be in full swing by next year.

Chinese tourists spent some $1 billion in Russia last year, according to a recent estimate.

Russia's new "red circuit" finds a counterpart in China, where Russian tourists can retrace the life of Mao Zedong, the first chairman of the Chinese Communist party.