Brīvības iela is the central street of Riga, the capital of Latvia. It is more than 12 km long, going through all of Riga from the historical centre to the outskirts.
Route starts in front of the Freedom Monument (Brīvības piemineklis), which is considered an important symbol of the freedom, independence, and sovereignty of Latvia.
Route is pretty straight forward - in the most literal sense - and ends just a few meters beyond Riga border by the border sign RIGA, which is also one of the national protected cultural monuments.
Check out Wikipedia for sightseeing possibilities along the way.