I took turkish airline, which results in me having a 6 hour stopover in Istanbul.
So i decided to venture out to the city centre on my own.
I landed in Istanbul- Ataturk airport at about 06.40am.
Dropped my baggage off at the counter upon arrival.
(Best decision because the journey to the city was really squeezy)

There are several ways you can get to the city centre.
1. Havatas
Which is a private company operating bus services to Taksim Squre.
Cost: 12 Turkish Lira
Frequency of bus: every 30 minutes
Duration: 40 mins

2.Metro

Follow the signs form arrival hall to walk 10 mins to metro station. 

Purchase a Jeton(ticket) from the ticketing machine.
Cost: 4 Turkish liras.

I took up the second option- metro, as i want to get to Sultan Ahmet (Old City).

I spent quite some time figuring out at the ticket machine. 

But thankfully i met a kind local that helped me purchased my tickets.

In order for me to get to Sultan Ahmet, 

i also have to stop at Zeytinburnu and change to Tram (T1)

It was during the peak hours, and the tram is super crowded. 

 Was greeted with this sight after i alighted from the tram.
Even though the sun was bright, it was freezing cold. 

 Since i only got limited amount of time, i visited The Blue Mosque.
Head coverings and also pants are provided at the entrance.
It is also free of charge to visit the mosque. 

 Right up ahead will be where Sophia Hagia is located.

Ticket price: 40 Turkish Liras (approx 18 SGD)

Good thing is that the major attarctions are nearby one another. 

I only walked around the building and headed for lunch at a restaurant around that area. 

 Turkish coffee during my meal (:
The owner of the restaurant kindly invited me in for some turkish tea too.
It is very common and their tradition to invite people into shops for tea! 

These are pretty expensive, but it's good to try them out.

Would definitely want to visit other places in Istanbul, like the Grand Bazaar. 
Also, to try out other turkish food.

Got back to the airport and boarded my plane to Warsaw-Poland at 1.30pm.