Sandstone cliffs surround the valley through which the Neckar River flows in southwest Germany. It's one of Germany's most scenic bike paths.
Mannheim -- the beginning of the bike tour along "Castle Road"
Castles and stately homes pop up along the trail, which on warm days attracts plenty of cyclists. The popular route cuts through vineyards as well, making its way through small towns with half-timbered houses as well as the picturesque city of Heidelberg.
The tour begins where the Neckar River meets the Rhine, in the city of Mannheim.
With a population of 325,000, Mannheim is easily accessible by train, and worth a stop to tour the baroque castle which houses the city's university. Walk over to Friedrichsplatz to see one of the largest art nouveau style fountains in Europe.
Then head to the north of Mannheim's inner city, where the Neckar flows along with rows of cyclists making the 130 kilometer trek up to Heilbronn.
"Castle Road" and stately homes
"Castle Road" also runs parallel to the Neckar along this section, and a paved road leads as far as Heidelberg. The route follows the river at first, then later moves through open fields with views of the Odenwald and Koenigstuhl mountains.
Just before Heidelberg, the route forks, either passing over a bridge leading to the town of Ladenburg or along the river's right bank towards Edingen-Neckarhausen where there's the option of transferring to Ladenburg by ferry.
With its old city center, marketplace and half-timbered houses, a visit to Ladenburg is like taking a trip back to medieval days.
The route takes you through picturesque Heidelberg
Whichever route you go, a short time later you will arrive in Heidelberg, a popular tourist destination because of its fine stately homes, old bridge, castle ruins and baroque city center.
After a few kilometers cycling along the main road, the scenery becomes more idyllic as you pass through Neckargemuend and Neckarsteinach with its four castles.
Small towns worth a stop
Shady paths then lead along the Neckar to Hirschhorn, which also has a castle, before arriving in Eberach, with its old town hall.
Castle Zwingenberg, one of the best preserved residences in the Neckar valley, is situated on steep cliffs on the river's left bank. To get there, though, you have to take another ferry.
When water levels are high, the ferry remains docked, so you may need to take a detour over the hills or along the main road on the opposite bank.
After arriving in Neckargerach you cross the river once again by bridge and cycle along a paved path beside green pastures towards Obrigheim.
Last stop on the tour is Heilbronn where the cycle path and Castle Road go their separate ways.
It's also the spot where you have the choice of either continuing cycling to Neckarursprung on the edge of the Swabian Alb plateau or along the Castle Road which leads to historic city of Nuremberg.