Thanks to Hilly Coufreur – Cambridge Library WAIPA DISTRICT COUNCIL for the photos and description of this display.
We glued the milk bottles with a hot glue gun. We started with a big cardboard circle cut from a fridge box. Then glue the layers and remember to leave a gap for the entrance!
For those who want to know: we used 434 bottles!!
Unfortunately it has now collapsed, the hot glue got brittle and didn't adhere enough. So with hindsight I would recommend if anyone attempts this to use really good glue.
The internet and YouTube have good examples on how to build an igloo from milk bottles.