290 Kms from Katerini
1. Athens: I would recommend staying in a hotel with metro access. We stayed in Athens for a couple of nights at Hotel Areos (100 EUR per night) and found the location to be quite convenient. The hotel is a 5 min walk from Victoria station (See map below). Victoria is a couple of stops from both Monastiraki and Syntagma and a very convenient base to explore the city. The area is also less expensive as compared to Monastiraki.
286 Kms from Katerini
The Berat Castle Present day host to a bustling neighbourhood, the Berat Castle is a 13th century monument. Along the narrow streets within the castle is the charming assortment of Byzantine churches and Ottoman mosques.