The next day was the main theme of this trip. We went to Auschwitz concentration camp. Most tourists went to Auschwitz from Krakow because this was rather close to Auschwitz and convenient in traffic. From Krakow you can to there by train or by bus. If you go by train, you may need to walk 2-3km to Auschwitz so most people will go by bus.
Second point that you should know is that when you visit Auschwitz, you may choose to follow their guided tour or you may choose to visit by yourself. The entrance is free of charge but you have to pay if you join a guided tour. The guided tour is about 2 hours, I think, which different languages. You can go to their booking office to register if you want, or you may do it in advance via online booking. If you choose to visit on your own, it is strongly recommended that you made your reservation online because the quota for individual visitors is very limited. In addition, you are not allowed to visit alone after 9:00am till sometime around 16:00pm, and you have to join group tour after March.
Therefore, it explained why I picked Poland as my first stop to visit, not the other way round, so that I arrived at Auschwitz in March and I can visit alone. I booked my visit time at 8:00am, which meant that I had to catch a bus to Auschwitz at 6:00am.
Personally, I do not think a tour guide is necessary as most of the information were shown on the explanation notes attached to the exhibits. Besides, you may use the money for guided tour to buy a guide book which gives more details.
There were a lot of people visiting there. We arrived at the site at 7:40am and there were already a crowd on the queue. As we made our reservation online, we needed not to queue and can go straight into the camp by showing our pass printed at HK during reservation.
Another interesting point is that you are only allowed to bring a small bag into the camp. All other backpack, handbags, etc had to be left at locker room. This is because long time ago there was a group of student who stole something from the camp........I don't know what is so valuable to steal......