The volumetric calculations for the city are as follows:
3,375,000,000 cubic miles.
To put that into more perspective:
1 cubic mile has 147,197,952,000 cubic feet - that's 147 Billion, 197 million, 952 thousand.
The New Jerusalem is mentioned in the book of revelation - Rev 21-22
This is the final dwelling place for all who have been saved by Christ. It will also be the home in which God himself, and Christ will abide.
It will be an eternal structure, which will never need repair or re-building.
Look at the picture showing the yellow line: this is just one side of the New Jerusalem - a city is so big that it spans all the way from London to eastern Greece. The city will be 1500 miles in length, width and height, making a perfect cube shape! and made of pure gold, transparent as glass! It will also have three entrances/gates on each of the four sides - each entrance is made from a single pearl.
Can you imagine how many rooms and different areas this city will have? It is actually hard to even imagine! You would certainly have a good view 1500 miles up.
God himself and Jesus Christ will dwell in
the city - so heaven will no longer be 'home' to them, but rather the New Jerusalem will.