The watching platform on top of the St Olaf’s (Oleviste) church is definitely a must visit place. It is probably one of the best possible viewpoints in Tallinn and definitely the best one to observe Old Town from a height.
It is believed that it was the tallest building in the world from 1549 to 1625 so climbing up there can be a challenge – in addition, the stairs are narrow and dark (you have been warned!). If there is oncoming traffic, you have to wait.
Still, despite all these difficulties I keep going there with almost all the travellers that I show the city around to. Usually it’s closed for the cold season and open from April to October only, so now is the right time to use an opportunity to visit it.