Looming impressively over the city of Heidelberg, 
you can well imagine that this was done to intimidate the enemy. I certainly was intimidated by the thought of walking up all 310 knee crunching stairs!
You can stroll the gardens for free, but you need to purchase a ticket to enter the courtyard of the castle. The ticket was €2. This gets you into the pharmaceutical museum, the exhibit on the Middle Ages and the Age of Romance, and the hall where the giant wine vats are located. If you want to see the interior rooms, you need to go on a guided tour at an additional cost of €3. We took the 2:15pm tour in English.
You will need at least half a day to do the castle justice. The exhibit on the Middle Ages on the first floor has displays in English, so it is enjoyable to visit. There are displays covering the history of Heidelberg and its rulers and a very nice suit of armor.

Upstairs, the exhibit on the Romantic age centers on Heidelberg in the arts. You can see drawings, paintings, and poetry, and if you have a few minutes, you can sit and listen to music.
The Pharmaceutical Museum offers an interesting display on the history of medicine, pharmacology in particular. I was fascinated by the display telling about the medical school in Salerno, Italy, where, in the 11th century, ancient medicine was taught to clerics and laymen, Christians and Muslims, and even women. Who would have imagined that! There are displays of pharmacies from the Middle Ages on a very interesting stop.
Our guide Kunegunde met us in the hallway of the building with the Middle Ages display. We are taken into another part of the building and familiarized with the history of the castle and why it became a ruin. There is no love of France displayed in this room since Louis XIV is the cause of the downfall of the schloss. We get to go through rooms decorated in a lavish style, as well as to walk up cold and slippery stairs to the turrets.

This is where all the interesting facts will fascinate you. You will walk on the terrace overlooking the old and the new moat and hear stories of hunting in the moat. This schloss is also a love story between a German prince and an English princess. The gate in the garden and even the gardens themselves are a tribute to that love.
If you need a food break, there is a café where you can purchase a snack or a small meal. We stopped for hot chocolate and cake. Considering that we were a very captive audience, the prices were competitive and the food quite good and very welcome on a cold and snowy day.