Where from does come such a light leak?

[werra]

Are there any buildings left in Tallinn from the time this part of Estonia was a part of the Swedish Empire, or did the russians demolish them?

There are for sure, at least in the Old Town. Renovated and modernized in past centuries of course, but nevertheless.

Most of the recent city buildings, 10 years or less, are in fact owned by Swedish Kingdom as well As they are mostly built with loans flowing thru Swedish banks.