Candles are lit mystery During the 1500 year

Australia Robbert Briggen a scholar, argues that prehistoric humans had intelligence that is more advanced than the knowledge that we have because they have eternal lights.

 
"In April 1485 the corpse of a noble lady of the ancient Greek era grave out of place in the" Appian Way ". When investigators entered the burial place, they were surprised to find a lamp that lights up from 1,500 years ago.

The question is in what ways our ancestors could make the light stays on to long? The mystery still remains a mystery is complicated but some experts still will continue to try to resolve this issue.

 
Some of them like Briggen, expressed the opinion that the energy used to light it is very likely been lost from the surface of the earth. However, there was no corroboration of his theories were. Smart people like what makes the lamp continued to burn until 1,500 years?