I visited this WHS in September 2016. I spent 3 days in Tallinn and was able to explore its historic centre quite well.

The cruise liner tour groups take over this small city from around 9am till lunchtime and again just after lunchtime till about 16:30. Of the 3 Baltic capitals this seems to be the most negatively effected from the huge cruise liner populations (most probably because of its size) but my early morning and late afternoon strolls helped to enjoy the main sites without the crowds.

To my surprise, unlike Carcassone in France, nowadays the city walls only encircle a small part of Tallinn. You can actually walk on most stretches of the city walls for a small fee. My favourite was the one with the Kanne Wall Tower as it is believed to be one of the oldest sections of the city wall (16th-17th century). Of the original 3km of city walls with 46 towers, only 1.85km remain with 26 towers.

The best places to take in the panoramic views are from the Oleviste Church Tower (picture) or on Toompea Hill from the Patkuli Scenic Viewpoint and the Kohtuotsa Scenic Viewpoint. The best place to take in the architecture and variety of buildings together with the walls is probably Kooli Street. Worthwhile visits (quite hidden) are the Ukrainian Orthodox Church (you have to knock and ask permission to visit) as well as the Old Dominican Monastery and Claustrum (even though 4 euros is a bit too much). I enjoyed exploring literally every street and alley of Old Tallinn and loved stopping for coffee and sweets at Maiasmokk.