Tallinn is probably one of the most beautiful cities I've ever seen and I grew up in Munich!
The capital of Estonia has more than 400,000 inhabitants, thus accommodates more than one-fifth of the Estonian population. These are just some facts. Nothing bad can be said about the city because Tallinn is one of the best and most beautiful old towns in Europe. Small winding streets, beautiful cafes, and even one of the best views from the top of the mountain town.
Every visitor of Estonia is recommended not to drive in winter or autumn. It was rainy for four weeks, only four days were clear. But once the sun came out, the city is on its good side.
In any case, you should then look at the Toompea and the Alexander Nevski Cathedral (and shoot some photos!) Oh, and also the Katharinental (Kadriorg) should not be forgotten, and so on. There is so much to look but I cannot list everything. You really should visit Talinn, one of the cultural capitals of Europe!