Certainly no one should miss the chance to visit the sacred rock of the Acropolis. You can admire the Propylaea, the Parthenon, the Temple of Athena and the Erechtheion.
The city view is unique and reaches down to the sea. Within walking distance is the new Acropolis Museum with its impressive architecture and many archaeological findings. Two sites and tracks of exploring that are worth being combined. You can walk around to the streets of Makrigianni Dionysiou Areopagitou and reach Thissio. From there you will be able to enjoy marvelous sightseeing of the ancient agora, the portico of Attalus and Keramikos. Always with the backdrop view of the Acropolis and magnificent neoclassical buildings that are scattered around every neighborhood.
The walk can be continued to Philopappos hill, the Temple of Olympian Zeus and Hadrian's Gate. All around these brilliant archaeological sites are picturesque neighborhoods of modern and contemporary Athens, like Koukaki and Mets. They form a separate piece of urban beauty and unique architecture as they preserve many of the features of the past. Around Mets, one can visit the Panathenaic stadium that hosted the first modern Olympic Games, while also the Zappeion, the National Gardens and the Greek Parliament.
In Plaka a particular point of interest is the area of Anafiotika. It is a district with a distinct Cycladic style, built by Anafi builders, who sought a settlement to make and call their home, while introducing the architecture of their place of origin. This architectural style is preserved until today. Guided by the narrow streets, one can reach the Athens Cathedral, the shopping street of Ermou with countless department stores, and continue towards Panepistimio and Kolonaki, the more upper class district of the city. There, you can admire the historic buildings of the Academy of Athens and the Library. The entire intermediate region of Kolokotroni Street and Karytsi Square are full of bars and quaint cafes that provide hours of leisure to spend your evenings by.
Then you can wander around the Monastiraki flea market and meet the more local side of Psyri. Taste the Greek delicacies found amidst the shops and stores, as well as international cuisine restaurants on your way to strolling towards Omonia and Varvakeio. There you can easily reach the National Archaeological Museum and the district of Metaxourgio.
Interesting additions to your walkarounds of Athens city may be the War and the Byzantine Museum in Vasilissis Sofias Avenue that starts from Syntagma Square. Hotel Nefeli comprises the ideal choice for city accommodation as it offers convenient access to all the attractions mentioned above.