Example:
speed of light in fiber, which is roughly 202562 km/s or or 125866 miles/s.
VM 1: e1-vm (Berkeley County, South Carolina)
VM 2: eu1-vm (St. Ghislain, Belgium)
Distance as the crow flies: 6837.20km
Ideal latency: 6837.20 km / 202562 km/s * 1000 ms/s * 2 = 67.51 ms
Observed latency: 93.40 ms (minimum counts)
https://www.daftlogic.com/projects-google-maps-distance-calculator.htm
https://cloud.google.com/compute/docs/regions-zones/regions-zones#available