The second largest city in Czech Republic is not normally on tourist itinerary. Brno is located about 250kms away from Prague. I visited Brno only because my spouse had to visit Gregor Mendel Museum but I discovered that the one other very good reason to visit Brno is Punkva caves. It is worth a day trip from Prague.
Travel from Prague
The best option is to take the train that runs at frequent intervals. I boarded a train before 8am in Prague and took a 7pm train from Brno to Prague later the same evening. The journey was quite comfortable and the train was about half full. The train takes about 2 hours and 40 minutes though few trains take little more than 3 hours. I paid approximately INR2k for the return journey in second class.
What to see and do in Brno
Gregor Mendel Museum
The museum is located within the campus of Masaryk University and is close to the main railway station. The museum has an exhibition dedicated to Gregor Mendel. Only the foundations of the greenhouse where the father of Genetics, Gregor Mendel, carried out his experiments on peas and other plants can be seen. The greenhouse was destroyed in a storm in the 19th Century CE.
For a general tourist, this Museum is not likely to create any excitement. But there is a monastery here as well for those interested.
Moravian Karst
This geological formation of caverns and gorges is located about 35kms from Brno and has over 1000 caves, of which very few are open to public. The place is called Skalni Mlyn and the most famous cave is the Punkva with its unique limestone formations. A walk through the caves located under a vertical cliff opens into the near bottom of the Macocha abyss. This abyss is more than 138m deep. This is followed by an exciting underground boat ride on river Punkva for about 15 minutes. The boat goes through narrow channels at times and I also had to ensure my head was at a safe distance from the ceiling! Photography was quite difficult inside.
Overall length is ~1.6kms, including the boat ride. I spent about 75 minutes in all inside the cave and thoroughly enjoyed every moment.
There is a café at the site and also a souvenir shop with several varieties of beautiful rock crystals. I purchased a fist sized blue rock crystal for about INR 2k.
Inside Punkva caves, Brno, Czech Republic 
The bottom of the Macocha Abyss, Punkva caves, Brno, Czech RepublicCzech Republic 
Punkva river underground boating, Brno, Czech Republic
Best to commute by taxi
The Vegan restaurant where I had lunch in Brno helped me in booking a taxi to Punkva caves and back and also negotiated a fair price. We also agreed that the taxi would drop me off at the caves and return for the pick up after 2.5 hours. Luckily, he did turn up else I would have been stuck as there is no direct public transport between Skalni Mlyn and Brno. The journey took about 45 minutes one way.
Stroll near Liberty(or Freedom) Square
It was almost 5pm when I reached Liberty Square and had couple of hours before boarding the train back to Prague. In terms of architecture, Brno is no different from Prague. I strolled around Liberty Square(called ‘Namesti Svobody’) which is said to be the main square and a popular meeting point in Brno, viewed the Old Town Hall and the Cathedral of St. Peter and Paul from outside and then walked to the railway station.
All said and done, Brno too is a beautiful city. If you skip Mendel museum, you could consider visiting the Spilberk Castle and Brno underground.
Vegetarian Food
There are quite a few vegan restaurants and also Indian restaurants. I had lunch at a vegan restaurant near the Mendel museum. Some of the dishes are designed to be a vegetarian replacement of a non-vegetarian item. It will look very obvious and hence easy to avoid. There are quite a few cafes and fast food joints and I packed a subway sandwich before boarding the train.
Commuting in Brno
Brno is well served by trams and trolley buses and these are adequate within the city. Best to download the tram routes in advance. Taxis too are easily available but if not going point to point, you may need help with language.
