In some parts of Germany, flood warnings have been lifted. But in other regions, such as along the Aller River on Wednesday night in Lower Saxony, the situation remains worrying.

Residents in Bremen found themselves having to construct their own bridges.

In some parts of Lower Saxony, local dikes were still in danger even though water levels had started dropping. Rescue workers on the banks of the Hunte River near Wardenburg came to help with hundreds of sandbags.

Near Wienhausen in Lower Saxony, volunteers built their own dike. In the city of Celle streets were closed off and two nearby holiday villages had to be evacuated when the power was shut down. Local media reported many in the community were helping one another and volunteering. By Thursday, high water alerts had not yet been lifted.

The Main River near Kemmern in Bavaria was still on the second-highest flood warning on Thursday morning. The river had risen more than half a meter (about 1.5 feet), authorities reported.

Ferry crossings over the Elbe River near the city of Dresden have all been canceled due to flooding. Service operators said the ferries could have kept running over the swollen river but other considerations also came into play, such as safety, water conditions and whether passengers could embark without getting their feet wet.

The small town of Windehausen in the state of Thuringia was one of the worst affected by the floods. With all streets underwater by Christmas Day evening and power and sewage no longer working, residents were asked to evacuate. Local media reported that 400 of the 500 residents had chosen to leave. It was "just like a bathtub that's been overfilled," Windehausen's mayor told local media.

On the evening of Christmas Day, hundreds of rescue workers formed a human chain to bring sandbags to a dike in the East Frisia region in the state of Lower Saxony. Dikes near Hollen and Langholt were in danger of breaking due to the heavy rainfall. Rescue workers told local media that their efforts had been successful and the dikes were still standing.

In the historic city of Dresden, mobile flood protection gates were installed on Christmas afternoon.

Dresden has seen worse flooding. Back in August 2002, the Elbe River overflowed and forced the evacuation of parts of the city, the state capital. Total damages from the 2002 flooding in Saxony were estimated at around €9 billion ($10 billion).

Each German state has different alert levels for flooding, with three or four usually the most dangerous and damaging. Hesse has three alert levels and most areas around the Lahn River (pictured here) were only at the first alert level.

The Bad Karlshafen gauge on the upper reaches of the Weser River in Hesse reached the highest alert level on Christmas Eve.

The Leine River flooded fields around Marienburg Castle in the Hanover area.

After days of heavy rain, the central Ruhr River also flooded in places. By December 26, water levels had started going back down again, authorities said.

Historic restaurant the Wurstküchl (or "sausage kitchen") has been serving up traditional German fare in Regensburg for 500 years next to the Danube River. On Christmas, it needed protection from rising floodwaters.

Regensburg's 12th century Stone Bridge is one of the oldest working bridges in Germany. Bridging the Danube River, it has survived numerous floods. But it has also needed renovations in recent years.

The Vils River flows through the middle of the Bavarian city of Amberg and broke its banks over Christmas. But by the afternoon of Christmas Day, the water levels were falling again, local media said.

In Duisburg, in the western state of North Rhine–Westphalia, measures were taken to ensure that the Ruhr dike wasn't breached. In the city, streets were closed due to flooding.