The World’s First Lightning Rod
After lightning strikes had destroyed many Stupas and monuments, Ancient Sinhalese Kings of Anuradhapura added metal rods to the highest point on their buildings to prevent such occurrences. This is evident in many ancient stupas and temples in Sri Lanka.
Although the Ancient Sinhalese knew that attaching a metal rod would prevent destruction from lightning, they were unable to understand the reason for this phenomenon. It was almost 2000 years later when American scientist and inventor Benjamin Franklin, proved that lightning was in fact electricity which could be conducted and grounded.
For a little more information about lightning rods in Sri Lanka ref to (pg 2) of the following link:
http://www.academia.edu/1745953/Lightning_rod
another link:
https://targetstudy.com/knowledge/invention/46/lightning-rod.html