There are 3 people 1 from China , 1 from America and 1 from India and all three of them are trying to prove whos country was more scientifically developed. 

(1) 
The Chinese man takes the other two along with him to china and digs the ground 200 meters he finds a phone cable and says >>my country had phones 200 years ago 

(2) 
The American man gets really frustrated and takes the other two to america, there he digs a hole 400 meters deep and finds a telephone wire, he then says >we had phones 400 years ago. 

(3) 
The Indian then takes the other two to India and digs a hole 800 meters deep but finds no wire at all he then says 800 years back we had mobile phones!!