US President Donald Trump has offered both candid praise and unabashed criticism of Germany and its policies. From calling German Chancellor Angela Merkel "possibly the greatest world leader" to describing her open-door refugee policy as a "catastrophic mistake," here are his most memorable quotes regarding Germany.

"Germany's like sitting back silent, collecting money and making a fortune with probably the greatest leader in the world today, Merkel," Trump said in a 2015 interview with US news magazine Time.

"The Germans are bad, very bad ... Look at the millions of cars they sell in the US. Terrible. We'll stop that," Trump said during a NATO leaders summit, according to German news magazine Der Spiegel, which cited sources at the alliance's meeting.

"As far as wiretapping, I guess, by - you know - [the Obama] administration, at least we have something in common, perhaps," Trump said in March during a press conference with Merkel. He was referring to his unproven allegations that ex-President Barack Obama tapped his phone. There was widespread anger in Germany in 2013 when it was revealed the US National Security Agency tapped Merkel's phone.

"I think she made one very catastrophic mistake and that was taking all of these illegals (sic), you know taking all of the people from wherever they come from," Trump said in a joint interview published by German daily Bild and British newspaper The Times, referring to Merkel's open-door policy for refugees fleeing war and persecution.

"Despite what you have heard from the fake news, I had a great meeting with German Chancellor Angela Merkel. Nevertheless, Germany owes vast sums of money to NATO and the United States must be paid more for the powerful, and very expensive, defense it provides to Germany," Trump said in a two-tweet statement after meeting with Merkel for the first time in March 2017.

"The people of Germany are turning against their leadership as migration is rocking the already tenuous Berlin coalition," Trump tweeted in the midst of a row within the German goverment. He went on to claim that: "Crime in Germany is way up. Big mistake made all over Europe in allowing millions of people in who have so strongly and violently changed their culture!"

Article 50 of the Treaty of Lisbon gives any existing member of the European Union the right to quit unilaterally and outlines the procedure for doing so. It gives the state concerned two years to negotiate a deal for its exit. Once Article 50 is triggered, it cannot be stopped, except by the unanimous consent of all member states.

There are five elements in Article 50. They state that the exiting country must notify the European Council formally and that it is given a two-year period to reach an agreement. Article 50 also states that the country concerned cannot take part in EU’s internal discussions about its departure. The exit deal must be approved by a "qualified majority" and must also get the backing of MEPs.

The UK decided in favor of leaving the EU in a referendum in June 2016. After lengthy parliamentary debates and legal procedures, Prime Minister Theresa May looks all set to send a formal letter of notification to EU President Donald Tusk on March 29, which will trigger Article 50. Officials in Brussels have already outlined a divorce bill for Britain of between 55 and 60 billion euros.

The EU is expected to give a first response later this week. A summit of EU leaders on April 29 is then to lay down guidelines for the Brexit talks, which are expected to start in May or June. The hardest part of the negotiations will be determining the status of more than a million Britons living in other parts of the EU and of some 3 million EU citizens in Britain, and working out trade details.

By autumn this year, the UK government is expected to introduce legislation to leave the EU and put all existing EU laws into British law - the Great Repeal Bill. The possible move will annul the 1972 European Communities Act (ECA), which gives EU law instant effect in the UK, and give parliament the power to absorb parts of EU legislation into UK law, scrapping elements it does not want to keep.

EU leaders have said they want to conclude the talks within 18 months to allow the terms of the exit to be ratified by UK and the European Parliaments as well as the EU states. If no agreement is reached in two years and no extension is agreed, the UK automatically leaves the EU and all existing agreements.

The fifth paragraph of Article 50 raises the possibility of a state wanting to rejoin the EU after having left it. This would be considered under Article 49.

Merkel has become known for using the same hand gesture at public appearances and in front of the camera, putting her fingertips together to form what some call the Merkel-rhombus – or in German, the "Merkel-Raute." If she has done so consciously or as a routine gesture out of habit is a question that have contemporary critics and journalists puzzled. Just what is she trying to say with it?

The German chancellor is known for her commanding and engaged appearance, often appearing quite somber, especially in Europe. Though she has been known to crack a smile at the right time, here, at the recent European leaders summit in Bratislava, she was more composed. To her left is Danish Prime Minister Lars Lokke and to her right, the Prime Minster of Belgium, Charles Michel.

Merkel has come into the spotlight for her response to last year's influx of refugees.. Questions about her response to the crisis can be answered when elements of her personal life are considered, as Rinke does in his book. She frequently visits schools and refugee shelters and while doing so, takes time out for selfies, as here in 2015 with Syrian asylum applicant Anas Modamani in Berlin.

As chancellor and head of the CDU party, Merkel faces a bit of difficulty in remaining considerate with some of her working partners. She does not respond with the huffiness her SPD party colleague Sigmar Gabriel is known for. Against attacks by the head of CSU Bavaria, the "archetypical Bavarian man," Horst Seehofer, she responds with cool objectivity.

For trained physicist Angela Merkel, the world of the internet and digital media is said to be relatively foreign, although her team does now have an Instagram account, which is fed by her official photographer. Still, that didn't stop her from grabbing the ear of Facebook founder Mark Zuckerberg at a lunch meeting at the UN in 2015.

The daughter of a Protestant minister, Merkel's values are said by Rinke to have been shaped by her Christian upbringing. In 2016, she was given a private audience with Pope Francis I at the Vatican, where the two exchanged words on their favorite books.

Merkel is not known to let it all hang out and, though rare due to her full schedule, celebrations are done in style. In 2013, in honor of the 50th anniversary of the Élysee agreement between Germany and France, Merkel invited the entire parliament to toast the two countries' friendly relations over champagne.

The chancellor gets only a few free vacation moments each year and even when on holiday, as here in Poland, she is not free from the prying eyes of the public. Her husband, Joachim Sauer, also pictured here, is rarely in the spotlight.