The first pavilion, which I’ve visited, was a Russian one because I’m Russian. There you can try delicious Russian food.
Next to Russian pavilion is Estonian one.
The ticket you can buy right at EXPO (when you get off the metro or train in a ticket office) and it is better to come a bit earlier (around 6 p.m.), because there will be a super long line to get in the EXPO in the evenings and especially at weekend, so be ready to be patient enough to wait and probably to get inside around 7:30 p.m.
architripture 