Yep, we were there also ... already the first day of our trip as it was so close to Ventspils where we got off the ferry. Think we visited like 30-40 abandoned places, either secret cities or just launch sites for intercontinental missiles. As we was travelling with dirt bikes we could easily access all without drawing to much attention ... it was easy to see when we came close to something military as it suddenly was concrete roads with large radius curves in the middle of the forest ... most probably transport roads for the trucks that should take the missiles from storage to the launch site. Both Latvia & Estonia was amazing to ride through with dirt bikes with all these sandy trails & small gravel roads ... the trip was in total 10 days & we traveled between 250-300km /day.