As someone born in Delhi, I am accustomed to walking past very old monuments. Sadly, I’m also accustomed to thinking that they will perforce be dilapidated, disrespected, and generally ignored. So Istanbul is a pleasant surprise.
Hagia Sophia for example (Aya Sophia), the now-museum, once-mosque-and-once-church, the awe-inspiring edifice I walked past fairly frequently is a lot older than the Qutub Minar, a structure I drive past when I am en route from Gurgaon to Delhi often.
And the former is much better maintained than the latter.
And if Aya Sophia seemed old, consider the more than 2000 year old ruins of Ephesus on the west coast of Turkey, on the Aegean sea.