Not all of the murals in Tallinn's Telliskivi neighborhood are sanctioned or commissioned. Just wander into the parking lot adjacent to the train tracks and you find several long walls full of guerrilla murals and graffiti.
Tallinn's Cultural Kilometer is neither a kilometer long, nor does it feature high culture. However, wandering on and near this 2.5 kilometer long pathway will show you a fine selection of street art and graffiti. There are murals and graffiti inside the cruise ship terminal area, along the Cultural Kilometer and (for as long as it's standing), on the old Patarei prison.
The cultural corridor runs from the Linnahall ruin west to Kalasadama street. It's easily walkable from the cruise ship harbor, Telliskivi and Old town, and you can find it on Google maps. Within the corridor, you'll find graffiti on the crumbling ruin of the old Linnahall and commissioned Mextonia murals representing Estonian culture along the pathway.
Taking a Street Art Tour in Tallinn
You can self-guide most of the pieces by wandering around Telliskivi, Kalamaja, the Cultural Kilometer, and peeking through the fence in the cruise ship harbor.
This is an excerpt and you can learn more by reading the full article on street art in Estonia at Wayfaring Views.