Here are plans for Eco-City 2020, a 100,000-person domed city built in the kilometer-wide and 550-meter-deep Mir diamond mine in the Yakutia Republic. According to designers AB Elise, the mine will be powered by the Siberian sun.
Here's a description of AB Elise's plan from Evolo:
The new city is planned to be divided in 3 main levels with a vertical farm, forests, residences, and recreational areas. On of the most interesting aspects of the proposal is the glass dome that will protect the city and would be covered by photovoltaic cells that will harvest enough solar energy for the new development.
According to Russian news, this project is more speculation than reality, but it certainly provides for some gee-whiz visuals.