Eighty years ago, on May 15, 1935, the very first line of the Moscow metro was officially unveiled. Running from Sokolniki to Park Kultury, the line was just 11 kilometers long and featured 13 stations. But from its humble beginnings, the Moscow metro has since expanded to become the world's busiest underground rail system outside Asia, with over 9 million journeys made on the network every day.

Today there are 196 stations in the capital's subway system (44 of which are cultural heritage sites), and the network is continuing to expand: This year seven new stations will open. The trains run along 12 lines with a total length of 327.5 kilometers, with many connecting stations having signs in English. Since trains arrive at the stations at an average of one every two minutes, there is never any need to worry about missing a departing train.

However, the Moscow metro is far from merely functional. The system is considered the most beautiful metro in the world, with the opulent decoration of many of its older stations leaving newcomers astounded. Many visitors have compared grand stations such as Komsomolskaya and Novoslobodskaya to underground palaces, and guided tours of the network are popular with tourists. The Moscow metro even has its own museum, located at the Sportivnaya station.

However, for various reasons – one of which was the tram lobby – these early proposals did not get anywhere. By the beginning of the 1930s the ideas gained renewed popularity, but according to engineers, the environmental conditions did not permit their realization.

According to Natalya Dushkina, architecture historian, professor and granddaughter of one of the most important metro engineers Alexei Dushkin, the engineers from London, Paris and Berlin who were invited to Moscow for consultation were "convinced that it would be impossible to build a metro here" due to the incredibly difficult Moscow ground.

"But thanks to Russian engineers, hydrogeologists and architects, Moscow created a system of enormous underground space – squares and streets of a real underground city that duplicated the capital," says Dushkina.

"My architectural credo is the Kropotkinskaya station," said Alexei Dushkin. "In order to create it we had to study the annals of Egyptian underground architecture. The top of the columns, illuminated by oil dies in the underground labyrinths of the pyramids, were used as a construction model. It reflects the functional reality that needs to be responded to. I love the Avtozavodskaya station because it was built in one breath. It clearly expresses the constructive essence and, as in the Russian churches, the purity of the working form."

The revolutionary architect here is without doubt Alexei Dushkin. Besides many others, he built the first station in the world with a deep foundation and columns instead of pylons, Mayakovskaya. Natalya Dushkina says that in the ratings of the best stations published for the 75th anniversary of the metro, her grandfather's Kropotkinskaya, Mayakovskaya and Ploshchad Revolyutsii were the top three.

Dushkin was "one of the founders of the Moscow school of metro construction, creating the principles of working underground," says Natalya Dushkina. First of all these principles regarded the station's clearly expressed constructive basis and the importance of light in the creation of an architectural structure in an underground space.

"Kropotninskaya uses hidden light sources, light that is softly diffused throughout all the space, creating the effect of an ethereal palatial enfilade. At the Mayakovskaya station Dushkin bored what he called "periscopes" in the vaults, decorating them with mosaics," explains his granddaughter.

"Moreover, he was a pioneer at mixing various forms of art underground, combining them with the latest technologies. He was the first to use sculpture (Ploshchad Revolyutsii) and glazed mosaics (Mayakovskaya) in stations. He was the first to introduce finishing material (the polished steel at Mayakovskaya). And after the war he used aluminum at Novoslobodskaya, as well as the novelty of stained glass. Finally, in 1943 he placed granite in the metro at Avtozavodskaya, underlining the importance of hard materials for covering the floor [before this asphalt or ceramic tiles had usually been used for that purpose]."

It contained a bunker and even a maternity hospital, in which 217 children were born.

Moreover, when the threat of invasion had passed, work recommenced on the construction of new stations. During the war seven stations were constructed, including Avtozavodskaya (a graceful colonnaded station that Dushkin considered one of his best) and Novokuznetskaya (designed by Ivan Taranov and Nadezhda Bykova).

At Novokuznetskaya it is worthwhile not only to examine the mosaics of the central hall, also designed by Deineka and dedicated to life and work on the home front, but if you go up the escalator, you can see the first Moscow metro vestibule to be built in the form of a rotunda with a cupola (created by architects under Vladimir Gelfreich and Igor Rozhin).

The security system in the metro featured various bunkers and the so-called Metro-2 – the governmental military lines of the metro, which got their name in the beginning of the 1990s thanks to authors from the magazine Ogonyok. One led to the airport at Vnukovo, the other to Kuntsevo, to Stalin's dacha. "But besides the rumors about Metro-2, we actually know nothing about it," says Anna Ludina. "And the bunkers, well, Stalin had several of them. We don't know about most of them, since they are closed. But there is an open one in Izmailovo, which has been transformed into the Stalin Bunker Museum."