First stop is the Latvian Academy of Sciences. This is on the edge of the old town and a Soviet era building mimicing the Seven Sisters in Moscow. I have visited most of these and even stayed in one that is a Hilton as well as going up the similar building in Warsaw. I quite like the look of them.
https://en.wikipedia.org/wiki/Seven_Sisters_(Moscow)
It's the tallest building around and provides panoramic views at the top. While I was there I was the only person on the viewing platform. So it's either not a routine stop of the tourist trail or everyone else is starting their day later. I would recommend it as a stop, the views are great. And it's also close to the Central Market which was my next stop.
Walked to the academy via the banks of the Daugava river and picked up a few other sights along the way.



Three Sisters

House of the Black Heads

Monument to 1905 Fighters

National Library

Wooden House