If time is a relative perception how does one understand archaeological ruins and atom decay?

although i feel i can understand how depending on the speed on which one travels and the frequency in which one perceives affects the notion of 'time', i find myself challenged to understand the physical manifestation of the ping of time on our plane. If we are living in the same point (space and time constriction to the limit) as the ancient greeks then what is the process that makes us see the buildings as ruins? Thank you anyone who might try to clear my confusion! :)