We had done a tour with the same company in Sofia so expected a good tour. We turned up planning to go on the free Plovdiv tour but as it was a weekend there was a surprise 2nd option of the socialist architecture tour so we elected to do that for something different. Our guide was excellent and knowledgeable on the history and architecture styles. We managed to go inside the post office with mosaics and woodwork you wouldn’t normally see (see sneaky photo). We also went inside the library but this time definitely no photos but worth going in to see the mural, stained glass and etchings. If you have chance do this tour.