Even thought Istanbul Aquarium is a little bit far away from other tourist attractions, it's a really beutifull place. Its the only place in Turkey that I have seen real penguins and they were amazing. Aquarium has so many species and you can see sharks, stingrays and penguins. Istanbul Aquarium ıs the best Aquarium I have ever been in my life. You will amazed by the sea creatures inside! You can go too the aquarium by using marmaray and Its worth your time for sure.