'Forget your past! Forget your history!" A colossal bullfrog of a guard, in an olive-green uniform with red epaulets, is spitting at us in Russian while a huge alsatian strains at the leash, barking ferociously. "Welcome to the Soviet Union," snarls the guard. "Here you are nobody!"

I can't say I wasn't warned: I had just signed a health and safety waiver that included the following clause: "In case of disobedience participants may receive psychological or physical punishments." This is 1984: Survival Drama in a Soviet Bunker, a three-hour long, quasi-theatrical experience in a genuine Soviet bunker in the middle of the Lithuanian forest; imagine Punchdrunk Theatre Company run by retired KGB officers. While most former Soviet republics have let their memories of the period fade into red mist, 20 years since the Russian tanks rolled out, Lithuania is confronting its communist past head-on.

An hour earlier, Ruta Vanagaite, the creator of the Soviet Bunker, was setting the mood. "Someone always faints – our record is five people fainting in one show," she explained matter-of-factly, re-assuring me that my translator will have smelling salts handy. "But be sure to answer the guards' questions promptly and clearly. They are mostly actors, but they can get stuck in that time and forget they are actors. We had to fire some of them because they were a little too hard on people. It's very easy to break people's will – once you are down there, six metres underground, you feel like you can't get out."

Just by the Neris river, towards the Belorussian border, a red flag by the side of the road indicates a turning into the forest, down a path towards an anonymous, decrepit building in a small clearing. Inside, Soviet anthems blare out from a creaking old radio, the paint is not so much chipping as crumbling off in blocks, the few striplights that are working are flickering maddeningly, and damp swarms over the walls like triffids. We are given mouldy overcoats that are so damp they're virtually liquid, and a cup of Soviet coffee – coffee with no coffee in it, made from barley. As we wait for the actors to show up (several of them genuine ex-KGB), the 40 or so participants, mostly Lithuanians in their 20s, laugh at the absurdity of it, smirking at the kitsch costuming. This, it becomes clear, is the fun bit. "Do you guys understand Russian?" asks a Lithuanian comrade. An Australian, Matt, answers for both of us: "I understand people with dogs shouting at me." Vanagaite chips in to tell us the alsation's day-job is working in the police's organised crime squad, digging for corpses. Oh good.

The bullfrog-guard enters and gives us our orders: we will answer only in the affirmative or negative; dissent will be punished with beatings and solitary confinement; and we will forget all thoughts other than the glory of the socialist paradise in which we now live. We stand to attention for the Soviet anthem and hoisting of the red flag, and then down we go, into the freezing-cold bunker. For three hours, we are force-marched through icy, virtually pitch-black corridors, barked at (by canine and human alike), humiliated, interrogated, forced to sign false confessions to imagined crimes, shown propaganda, and taught to prepare for a nuclear attack by the imperialist pigs. Each stage is designed to illustrate, with little allowance for subtlety – or health and safety – an aspect of life in the Soviet Union.

Having failed to answer a question correctly in Russian, I get it repeated in broken, angry English. The interrogating KGB officer pushes me against a filing cabinet. "Where are y'fRRROM?" England, I say, cowering. He prods me in the chest, hard. "You are English? English spy! English spy!" In another "scene", a KGB doctor forces me to strip to the waist, in front of the other participants. "Jacket off! Shirt off! Strip to waist! Quick! Quick!" She sits me down on a stool, grabs a clump of cotton wool, douses it in alcohol, and sets it alight. This is then dropped in a glass jar and applied to my bare shoulders: known as "fire cupping", it was supposed to draw out disease through the skin.

Six metres underground, and comprising 3,000 square metres of tunnels and cave-like rooms, the bunker was built in 1984 as an emergency base for Lithuanian state TV transmissions, in case the capital Vilnius came under attack from Nato. It boasts stand-alone heating and sewerage facilities, and communication lines to Moscow, and a roof designed to withstand the impact of a nuclear bomb.

Those seeking even grimmer times can visit the Museum of Genocide Victims in Vilnius, where they can see old KGB cells. Photograph: Alamy

Ignes, the young project administrator, thinks it is more of an educational experience than a dramatic one, especially for those, like him, who are too young to remember the parades, the food shortages, the paranoia and the rest. His parents would never even dream of enduring the bunker, he laughs, "but for us, for my generation, we should all come, so we can feel what it was like too". This isn't the first time a Lithuanian in their early 20s has used that very physical verb about their Soviet history to me – you have to "feel" it; just reading about it isn't enough, because it is almost too strange to be believable. "The young people, they don't understand what it was like," Vanagaite insists. "They say: 'How come you couldn't get out of the country? You just take a train and you leave.' They think they could just overpower Soviet guards. We try to show them the reality."



Less theatrical, but equally harrowing, is the Museum of Genocide Victims, housed in a former KGB prison in central Vilnius where hundreds were tortured and killed. The exercise yard is adorned with poignant children's paintings in response to school trips here. "We encourage them to imagine what it was like," says Remigija Paldauskaite, herself only five years old when the Berlin Wall fell. "The best way to learn it is to feel it." She mimes a bored child flicking through a text book. "It's a better way than history lessons."

The final, stunning plank in the trinity of Lithuanian exercises in Soviet memory is Grutas Park, known slightly glibly to some as "Stalin's World". It is not exactly a theme park (though there is a playground, and a zoo featuring llamas and bears), but a massive outdoor collection of the country's Soviet-era statues, as well as log cabins containing thousands of other exhibits, from rugs with Lenin's face on them to Pioneer drums, communist toys, flags, paintings and Soviet-era calculators. Now celebrating its 10th anniversary, this macabre oasis of socialist realism was built on snail money (the owner Viliumas Malinauskas is a wealthy snail and mushroom farmer), and is situated deep in the tranquil Lithuanian forest. It is a surreal experience, walking for a mile through the tiny village of Grutas, past a solitary fisherman sitting by a lake, to discover a world where Stalin stands quietly gathering cobwebs in a clearing, and Marx and Engels peek out from the shadows. Glimmers of sunlight pass through the cedars, dappling totemic statues to collective farm chiefs and partisan martyrs: it's both fascinating and oddly beautiful.

Lithuanian schoolchildren pose beside a sculpture of Stalin in Grutas Park, Vilnius. Photograph: Alamy

Malinauskas brought them there at a point when they were facing destruction, either deliberately or via neglect; the only Soviet statues left standing in Vilnius are the socialist-realist figures that adorn the four corners of the famous Green Bridge – and they are frequently doused in green paint by nationalist protesters.



But again, perhaps problematically, they are beautiful statues – inspiring, optimistic, and utopian; totems to the radiant future that was always promised, but never quite arrived. "We will never escape our history," the daughter of a Lithuanian communist chief said, upon visiting her father's monument in Grutas Park recently – and Lithuanians are rare in recognising that fact. Hungary has a monument park similar to Grutas, and so does Poland – but generally former eastern bloc countries have chosen to remember the cold war by trying to forget it, sweeping their Lenin busts under the carpet and hoping people won't trip up over them.

But then Lithuanians have a number of endearingly eccentric characteristics. This is a country where the capital's mayor travels everywhere on a Segway and is not ridiculed; beaver and mashed potato is served as a delicacy; and a high-profile monument has been erected to Frank Zappa, even though he never once visited, sung about – or even mentioned – Lithuania. The Zappa statue was audaciously suggested by local artists in 1992, as a slightly flippant test of their country's newfound democratic freedoms; to their surprise, the authorities called their bluff.

There are inevitable differences of opinion about how best to commemorate the Soviet occupation; Grutas Park in particular has attracted criticism for creating a shrine to communism, rather than a mausoleum for it. Vanagaite is dismissive of its softer approach: "What we are doing is the opposite of Grutas Park – you cannot buy anything here, this is not about nostalgia." She suggests that the extensive gift shop and nostalgia-channelling Soviet-style cafe – featuring "Russian-style sprats" and a minimal "Nostalgija" borsch – make it a "Stalinist amusement park". Grutas Park is unapologetic about using mockery as a weapon: on special occasions, they employ lookalikes to pose as Lenin, Stalin et al, and put on performances by young actors dressed up as Pioneers. "Now we can laugh at our Soviet past," announces the park's audio guide at one point. Vanagaite eventually agrees there is a role for this, as well as shock tactics: "I suppose it's about finding the right mixture of absurdity and horror." What they have in common is a recognition that, 20 years on, whether it provokes laughter or terror, the spectre of communism is still haunting certain parts of Europe – and ignoring the ghost is not going to make it go away.