10 Best Sights in Heidelberg and the Neckar Valley, Germany

This former residence of the counts and dukes of Württemberg was originally built as a moated castle around 1320. Wings were added in the mid-15th century, creating a Renaissance palace. The palace now houses the Landesmuseum Württemberg (Württemberg State Museum), with exhibits tracing the area's development from the Stone Age to modern times and a floor of jaw-dropping family jewels of the fabulously rich and powerful Württemberg royals. There's also a separate floor dedicated to a children's museum.

A wealth of vintage toys, model trains, and vehicles, including motorcycles, awaits children of all ages. This private collection, open to the public, includes Porsche, Ferrari, and Maserati race cars, an original 1957 VW Beetle, and a rare 1954 Lloyd. Ask a docent to start up the HO trains or one of the antique musical toys. Kids can ride one of the old pedal cars. There's also a small café.

The stunning futuristic architecture of this museum is an enticement to enter, but the equally stunning historic and futuristic vehicles inside are the main attraction. Visitors are whisked to the top floor to start this historical timeline tour of motorized mobility in the 1880s, with the first vehicles by Gottlieb Daimler and Carl Benz. Other museum levels focus on a particular decade or category of vehicle, such as trucks and buses, race cars, concept cars, and future technology, including autonomous driving. Historic photos and other artifacts line the walls of the circular walkway that links the levels.  There's a huge gift shop with all kinds of Mercedes-Benz–branded items and a new-car showroom you can muse over appealing models that are sold in Europe but not in North America. If all that technology makes you hungry, enjoy a full meal at Bertha's Restaurant, named for Bertha Benz, which serves farm-fresh local fare, or a quick bite in the Bistro or Deli.

In the center of the Porsche factory complex in the northern suburb of Zuffenhausen, the architecturally dramatic building expands outward and upward from its base, like a sports stadium. Inside is a vast collection of legendary and historic Porsche cars including racing cars, nearly 1,000 racing trophies and design and engineering awards, and several vehicles designed by Ferdinand Porsche that eventually became the VW Beetle. It is astounding how some 1930s models still look contemporary today. The museum includes a coffee shop and the Boxenstopp bistro, ideal for families, open during regular museum hours. There is also the sophisticated Christophorus restaurant, regarded as the best American-style steak house in Stuttgart, open Tuesday through Saturday until midnight. The gift shop sells some Porsche-branded logo clothing, but mostly miniature collectibles. Stand under the special "cones" on the upper level to hear the different engine sounds of various Porsche models, and try out the interactive "touch wall" timeline to explore nine decades of automotive history. Factory tours are available with advance arrangements.

One of the best-preserved Neckar castles is the 15th-century Burg Guttenberg. Within its stone walls are a museum and a restaurant (closed January, February, and Monday) with views of the river valley. The castle also is home to Europe's leading center for the study and protection of birds of prey, the German Raptor Research Center, with 100 falcons and other birds of prey. There are demonstration flights from the castle walls from April through October, daily at 11 and 3.

This museum, on the lower floor of the Ottheinrichsbau (Otto Heinrich Building), is filled with ancient flagons and receptacles (each with a carefully painted enamel label), beautifully made scales, little drawers, shelves, dried beetles and toads, and marvelous reconstructions of six apothecary shops from the 17th through the 20th centuries. The museum also offers young visitors the chance to smell various herbs and mix their own teas.

Displays include the 1885 Daimler machine that started us on the road to motorized mobility, the world's first mass-produced motorcycles (Hildebrand and Wolfmüller), and exhibits on racing. Also here is the NSU Museum, an early motorbike manufacturer acquired by the predecessor of the company now called Audi, which has an auto production facility in Neckarsulm. The collections are arranged over five floors in a handsome 400-year-old castle that belonged to the Teutonic Knights until 1806. The Audi factory in nearby Neckarsulm offers tours.

Billed as the world's only pig museum, it is housed in a former slaughterhouse, with displays on more than you ever wanted to know about breeding and porcine anatomy. Exhibits of piggy banks and other pig-themed memorabilia are fun to peruse. There's also a restaurant and an outdoor beer garden, and a play area for the kids where everything is pig-themed, from the seesaws to the garbage containers.

Germany's largest Romanesque living quarters and once the imperial women's apartments, this is now a history museum with relics from the Neolithic and Roman ages along with the history of the Palatinate, including medieval art, armor and weapons, and ceramics. Next to the Steinhaus are the remains of the northern facade of the palace, an arcade of superbly carved Romanesque pillars that flanked the imperial hall in its heyday. The imperial chapel, next to the Red Tower, holds a collection of religious art.

On the last weekend in August, the Old Town's medieval past comes alive during the Zunftmarkt, a historical market dedicated to the Zünfte (guilds). "Artisans" in period costumes demonstrate the old trades and open the festivities with a colorful parade on horseback.