It is free, it is extensive, it has evil Russian propaganda. Do I need to say more?…read more I do have to take off a star for not accommodating stupid Americans like me. Even with the audio guide, there are some parts of the museum that you will just have to squint at intelligently, take pictures thinking that you will translate when you get home (you won't), and move on with the other children to the big tank. Big tanks require no translation. Neither does the life-sized canoe crashing through the wall with life jackets pouring out of it (bet you're going now, aren't you?)

This is one of the best museums to visit if you are at all interested in contemporary German…read morehistory (WWII and on). While it is a bit frustrating if you don't know German (only the major captions on signs are translated into English, though I heard you can ask for an English guide), the fact that it's free more than makes up for it. Regardless of my utter lack of German language ability, I still managed to spend hours in this museum. The best part? Admission is absolutely FREE. Definitely a must-see attraction in Bonn. Go with German locals if you can; it'll likely make your visit much more meaningful. Note: You will be asked to turn in your personal belongings at the coat check. Also, there is a direct entrance to the museum from the Heussallee/Museumsmeile U-Bahn station, on the western side of Friedrich-Ebert-Allee -- going through this entrance will actually allow you to see a neat car and train.

This is a great museum for maths aficionados. Captures incredible history of Arithmetic in general…read moreand its cryptographic and more sophisticated discrete maths in particular. Several exhibits and all for about three euros fee. You can spend many hours on the four floors with some original but some replicas of some of the rarest calculation machines ever built. For English users, you have enough in English in terms of supplementary cards. Must visit if you are in Bonn.

Mechanical calculators? I literally cranked out numbers in this place. The old-school calculators…read morehad hand cranks to drive the mechanism. It was a lot of fun to be able to play with some of the display calculators. Most of the calculators that you can play with come with quite detailed instructions in case you want to follow along and understand the mechanism. A beautiful space, reasonably well documented displays (even with English info), and just the right size to spend about two hours museum-ing. The focus is clearly calculating machines, but there's art as well as modern furniture on display. In some cases, the modern chairs slightly upstage the calculators. The floors are laid out such that the top floor contains the most ancient calculators and each floor down gets us closer to the present day. Worth a visit.

This is the little brother to the Deutsches Museum in Munich. It's nowhere near as large, but has…read morean interesting collection of experimental artifacts with an emphasis on physics. (As an example, they have the vacuum chamber where fullerene was first synthesized.) If you're a scientist, you'll enjoy looking at the retro equipment (and recognize how many famous experiments were run on hacked together gear). There's also some hands-on for the kids. Plan an hour or two max, though -- it is much smaller than Munich.