1. The main building is in the centre of the space just like when they created victoian cities which often had a church /cathedral in the centre as the focus point for the community.
2. Large hatch at the top which allows daylight in for the plants but is only opened at certain times of the day so they are not caught by the martians.
3. Large water tanks holding water thats being piped from the river thames to all area's of the underground city.
4. Lots of use of iron as it was the toughest material around the time that they could manipulate into shapes they wanted to build with.
5. Lots of use of the colour white to make the light reflect around. With white tiles and white painted buildings.
6. Lots of levels - in the victorian era they started to build to a higher height with conventional 2 level house being pushed up to 3 or even 4 level houses.
7. Use of mirrors to reflect light towards the plants and help light up the area.
8. Large metal supports to hold up the tunnels so they dont collapse.