Revelation 21:15-17

The angel who talked with me had a measuring rod of gold to measure the city, its gates and its walls. The city was laid out like a square, as long as it was wide. He measured the city with the rod and found it to be 12,000 stadia in length, and as wide and high as it is long. The angel measured the wall using human measurement, and it was 144 cubits thick.