Visiting Jena it is a must to hike in the woods. It is situated in the Saale-Valley surrounded by the 400 m (1,300 ft) high Kalk-mounts. Here you find numerous hidden sights and have a wonderful view on the town of Jena.
More pix and info on my travelogue.
Jena has good transport connections all over the state of Thuringia, but also beyond to Saxony and Saxony-Anhalt. It's just an hour from Leipzig on the ICE, a couple of hours from the GDR museum piece of Chemnitz, and has regional trains to whisk you to little gems like Weimar and Naumburg. Like many towns in this region it makes for a very convenient base for exploring.
Jena's botanical garden is the oldest of its kind in Germany, and one of the most famous, due to its connection to Goethe, who spent a lot of time here in the late 1700's. In fact, two of the garden's prime attractions are a Goethe memorial and an old Ginkgo tree that Goethe reportedly imported himself.
Other highlights are the cactus house and the Victoria house (which displays unusual water-growing plants from the Amazon -see postcard).
You can also just walk around through the trees in the park and admire the various species of plant-life, including quite a large rose collection.
Opening hours: daily 9am to 6 pm in summer (15 May to 14 Sept) and 9am to 5 pm in winter.
Admission is 2 Euro for adults and 1 Euro for students, children, and seniors.
Pre-history, causes, course and consequences of the Battle of Jena and Auerstedt
The facility is run by the Institute for military-historical Research of Jena 1806 and is found on the site of the Jena Battle Field. The visitor will find contemporary exhibits about the battle and the war of 1806/07 between Prussia and France. Apart from detailed information about the causes, the course and the consequences of the Battle of Jena and Auerstedt, it also informs about the costs of the war, to be born by the people in the regions that were hit, about the every day life of the soldiers, their uniforms, and about the function and impact of the weapons of the Napoleon Era. Presentations and tours are available about: The Battle of Jena and Auerstedt on the 14th October 1806, complimenting the exhibition and the battle fields.