The traditional annual Christmas markets are gearing up across Germany, with their bright lights and treats for young and old alike. But since a terrorist attack rent the festive atmosphere apart in central Berlin two years ago, security has been another central theme.

The larger markets in Berlin in particular are taking no chances. The whole of the square in front of the landmark Kaiser Wilhelm Memorial Church where the 2016 attack occurred has been cordoned off with heavy steel barriers.

Pedestrian approaches and other access points have been blocked to vehicles with bollards and concrete plinths. The barriers are intended to provide protection against trucks weighing up to 40 tons.

It was here that an Islamist terrorist ploughed his stolen truck into the festive throng, killing 11 and injuring more than 70 at the market on December 19, 2016

At Nuremberg's famous Christkindlesmarkt by contrast, the solution is trees not bollards. The northern Bavarian city is putting up mobile Christmas trees to block the smaller access routes.

"In our case, erecting concrete bollards would only be possible with a lot of effort. The entire Old Town would have to be shut down for the work," Christine Schuessler from the mayor's press office said.

The streets of Nuremberg's Old Town are in any case mostly crooked, making it difficult to get close to the market at any speed. Where necessary, police will position large vehicles in the way.

Dresden's Stiezelmarkt, which claims to be Germany's oldest, opened in the last week of November for the 584th time.

Police have set up a mobile police station on the market, and security officials from the city authorities and a private company will also be on hand. As in previous years, there will be concrete obstacles in place.

New measures include two mobile barriers at entrances to the market and large foldable containers with water, as well as mobile vehicle barriers.

The Ruhr city of Bochum is also introducing fresh security concepts, blocking access routes to the inner city with dozens of large water bags that are said to be able to stop a truck.

The new system is replacing the previous one that used sandbags, a Bochum Marketing spokesman said. Truck-proof barriers are being erected at three points. The barriers, which are designed and made in Israel, distort on impact.

Not far away, Dusseldorf is to make use of large concrete blocks, while also deploying additional security forces, both uniformed and plainclothes.

Hanover has set up a mobile police station on the edge of its market, but is not making used of concrete barriers. The extended nature of its Christmas market renders attempts to block all access points senseless.

Bremen to the north-west is also doing without concrete. "They don't provide foolproof protection in any case," police spokesman Nils Matthiesen says.

In any case there is insufficient space in the ancient Hanseatic city. Police are relying instead on working with private security companies and mobile barriers for use in emergency.

Alongside the usual measures in concrete, Frankfurt is resorting to modern technology, including disseminating information by app and camera surveillance to safeguard its Christmas market.

"Over recent years we have improved our equipment and measures to such an extent that nothing more is possible," organizer Kurt Stroscher says, adding that any further security improvements could only mean cancelling the whole thing or shifting it to a military barracks.

Hamburg is leaving largely unchanged measures put in place last year, police spokeswoman Heike Uhde says. The northern city's police see the security risk at roughly the same level. Certain locations will be protected by concrete bollards, and the city's police will ensure a "visible presence."

In Rostock on the Baltic coast, the concrete bollards used last year have been replaced by steel versions, and the police presence will be boosted by a private security service.

Trier on the border with Luxembourg will see police from the grand duchy and from nearby France patrolling its streets on the busy Saturdays, alongside its own German officers.