Opel Zoo is a mid-sized zoo easily reached from the centre of Frankfurt, by S-Bahn + bus. I visited on a very cold day in early February, when it snowed. As such, many of the zoo's inhabitants did not come out of their indoor enclosures, but those that did were easy to see and photograph.

Highlights of what I was able to see include: brown hyena, red kangaroo, Arctic fox, and warthog The zoo lacks big cats, but does have lynxes and wildcats.

Animals viewable in their indoor exhibits include dwarf mongooses, African elephants, bush hyraxes, and Rothschild's giraffes. There is also a small aquarium and vivarium, although beware that in winter, the crocodiles are offshow, as are all of the European reptiles and amphibians that live in the outdoor enclosures.

The zoo is large and hilly, but there are routes which avoid the steepest of hills. There are a few reasons for my not giving 5 stars, one of which was the rough gradient; another was the invisibility of certain creatures because of the season, and the third was the kissing gates.

There is a public footpath that traverses the zoo, and as such, at two points, there are kissing gates that do not allow people entry to parts of the zoo, only exit. As such, I walked to one end of the zoo (past the kangaroos) only to realise I had to turn back and walk uphill to get to the entrance to that part. This may have been indicated as signage (not being so fluent in German, I may have missed this), but certainly was not emphasised on the map (that which I had printed and which was available at certain parts of the zoo). This did, however, give me another opportunity to visit exhibits that were previously empty due to the animals being indoors.

Allow 3-4 hours to see all parts of the zoo once, more if you desire to go back to parts you missed. Allow around half an hour to get there from Frankfurt Hauptbahnhof. This zoo's entry was more expensive than Zoo Frankfurt, partly due to the fact that the Frankfurt Pass does not entitle you to a discount.

Certainly worth a revisit next time I'm in the area during the warmer months of the year.