I’ve always told anyone who would listen I didn’t see the point in visiting places twice. Then I met Berlin and my rule was in tatters.

Its modern history reads like a scary novel - but one which drew me in for my first visit 15 years ago.

After being the epicentre of Hitler’s persecution of Jewish people in the 1930s, the postwar years saw the city divided into two regimes under the guise of German rehabilitation.

West Berlin flourished and became a haven for art and shopping under the (capitalist) administration.

The east of the city, which had always had an edgier reputation, languished under the (communist) German Democatic Republic (GDR).

Its chief feature was the feared Stasi – a network of spies and informers recruited from people like you and me to spy on people like you and me – ensuring that all important loyalty to one’s leaders.

There is quite simply nowhere else in the world that has developed in the same way, severed in two for nearly 30 years. And today, it still excites.

Of course looming in the background to all this was the feared Berlin Wall (1961-1989) designed to brutally stop the drain of people from the East who sought out a different life in the West.

One of the best places to see it is the memorial at Bernauer Strasse. Today it is an airy and buzzing spot with a low-key cafe culture.

But as The Wall became reinforced it found itself cut in two overnight. A 1.4km section is sensitively preserved and behind it, the system of watchtowers and death strips – to catch those who did try and escape.

A free-to-visit viewing platform gives visitors the chance to view the watchtower and series of barbed wire reinforcements and pause for reflection.

My visits to the city have spanned 2000-2015 and each time it feels like Berlin has become a bit more accepting of its past and is ready to explain this to outsiders.

In the early years you struggled to find traces of the GDR and what life was like under it.

A debate raged about how far a place should preserve sites such as watchtowers and death strips and they remained hidden.

Fast-forward to today and a new GDR Museum has opened on the banks of the River Spree. Shying away from artefacts in cabinets and information boards, it offers a taste of that life.

A typical flat offered by the state to workers is recreated with the equipment and even smells of the period and you can drive a Trabant simulator.

Life was often drab and colourless by our standards – yet people always had a job and a feeling of security many feel has been lost in today’s world.

But that security came at a price and to appreciate that a visit to the Stasi Museum is a must.

Its not a museum as we understand it, but the actual building (so a living memorial if you like) used by high-ranking Stasi officers.

You can stand in the office occupied by Erich Mielke – the head of the secret police force – and breathe in the atmosphere of a place used to command 92,000 professional spies and 170,000 voluntary informers whose work landed many in political prisons.

A new attraction gaining attention is Yadegar Asisi’s panorama of a divided Berlin. Visitors are taken to the middle of a 360 artwork showing the Berlin wall snaking its course through Kreuzberg and to the east.

It shows how close, yet how far, east and west really were and how drab and grey life in the east was - punctuated mainly by colourless high-rises, border guards, watchtowers and barbed wire.

The artwork, set in the 1980s literally took my breath away.

The point is you can’t escape from it as it is all around you. It’s as if the oppressiveness leaps out at you, even though you’re standing on a viewing platform looking at the scene. No picture of it can do it justice - you just have to be there.

The building housing the Asisi Panometer also features a moving exhibition showing people’s memories, through photos, of a divided Berlin and divided Germany.

Most moving are pictures of the same group of young men in front of the barbed wire separating them from the Brandenburg Gate - and again years later as middle-aged fathers when they could walk freely up to the iconic symbol of the city.

Berlin is the history of life and what people did to survive a harsh regime. Those who emerged in one piece often did so at the expense of others.

And this atmosphere is all mixed in with the landscape and the modern accompaniments we now so easily take for granted.

A short stroll through the city-centre takes you from modern gleaming shopping malls of Potsdamer Platz, past the memorial to the murdered Jews, to the Brandenburg Gate and then to the Reichstag.

And when you need lunch or a little snack – pay the entrance fee to another former symbol of the GDR – the TV Tower in Alexanderplatz and enjoy your food at more than 200 metres high.

Aside from history – for just a moment – who wouldn’t love a restaurant where the floor gently revolves giving you a 360 degree view of everything?

Mary’s travel around Berlin was funded by Visit Berlin Her flights and hotel were arranged independently.

Top tips
Berlin is literally packed with things to do and in a few days you will only be able to scratch the surface. Take some time to plan activities before leaving the UK by clicking on Visit Berlin
A free app giving you the lowdown on Berlin’s 12 districts and the attractions found there was a useful reference tool - both in advance and while on the go. See Going Local Berlin

Public transport is quick, efficient and easy to use. A network of trains (S-Bahn and U-Bahn) and buses run every day while trams tend to serve the outlying areas of the former East. A Berlin Welcome Card is a must investment. You buy a card for the length of your stay, but it comes with a large range of discount offers to tourist attractions - in some cases up to 50% off entrance fees.

Our Welcome Card saved us money off the fee to visit to the TV Tower and also got us a discount on our meal (pictured above).

While I love the history of spying, the cold war tensions and the divided city, don’t overlook the more obvious sights. The Reichstag (Parliament building) is a stunning centrepiece and is key to power being shifted back to Berlin from Bonn in the 1990s as the country reunified.

Take the chance to walk around a stunning glass dome, sitting atop the middle of the building’s roof and look out over the city. But booking in advance is essential as dome tours operate on timed slots.

Berlin is a city that likes to have fun and a bit of research before you go is recommended to help you uncover this before you go. Our must-do evening activity was visiting an open-air cinema (Freiluftkino). Held during the evening, we watched Dallas Buyers Club in English, in the middle of a large park by the former Tempelhof airfield, sat on wooden benches. You’re allowed to bring your own food and drinks and the night cost only 14 euros for the pair of us. A bargain. (But wrap up warm!)