The Irkutsk Hydroelectric Dam is the piece of Soviet engineering that turned the Angara at Irkutsk into a controlled reservoir system. It is not a beauty spot in the old-church sense, but it explains the scale of modern development around Lake Baikal's outflow.
View it from public riverfront areas rather than expecting a plant tour. The stop works best for travellers interested in infrastructure, Soviet urban planning, or the way the Angara River defines Irkutsk's geography.