Armand Hippolyte Fizeau:
a Rapidly Rotating Toothed Wheel
The First Terrestrial Method
The first measurement of c on Earth was by Armand Fizeau in 1849. He used a beam of light reflected from a mirror 8km away.
The beam passed through the gaps between teeth of a rapidly rotating wheel. The speed of the wheel was increased until the
returning light passed through the next gap and could be seen. Then c was calculated to be 315,000 km/s.
" (source: iastate.edu)
Find one 8 km clear line of sight ... or find a better way.
Actually bouncing a laser beam off the NJ's High Point Monument
on a warm summer night is quite an attractive thought.