Istanbul, a city of beauty and cats
First things first - if you are allergic to cats - I am sorry to say that Istanbul, or Turkey overall might not be the best place for your next trip. I would add here a link to cat allergy symptoms or to cat allergy medication but I am not qualified to share that information so I will just talk about what I know.
Istanbul is and always has been a center of... well... everything? Previously known as Byzantium, then Constantinople, now Istanbul, the city has been passed down from Greeks to Romans to the Ottomans in a location that is still crucial between Asia and Europe. But why does this matter, and why are you getting a history lesson on a blog that is definitely NOT a history blog? Because knowing that Istanbul has always been a hotpot for many cultures is the only way to understand the complexity and the clashes that you will see throughout the city.
I decided to visit for seven days, which might a few extra days than you might need, but with everything there being as cheap as it is (compared to Madrid or New York) it is doable. Also, given the amount of days that I stayed I was able to visit things at my own pace and enjoy the city itself, which in my opinion is better than just doing the touristy spots.
One spoiler: Istanbul is an old city. This means that half of everything you see will always be under construction. Very unfortunate, but that's the way it goes. With that said, here are some of the things I was able to see and recommend:
Museums & Places of Interest:
Topkaki Palace: The center of government of the Ottoman Empire between the 15th century and 1923, this palace is full of great artworks, and its architecture is something to be impressed by. If you get a good guide to show you around - that is a plus, as it can help put the Ottoman Empire into perspective along with the different sections of the palace. Make sure you don't miss out on the Harem, because it is mind-blowing (the tickets are sold at a separate place of where you buy the main ticket).
Blue Mosque: Everyone who has seen it says its a beautiful place. I unfortunately could not see the ceiling as its under construction right now - but what I saw was definitely stunning. The experience itself of walking in barefoot and just standing in this huge structure is humbling.
Hagia Sophia: This was a cathedral, which was then turned into a Mosque and is now a museum. It has been standing since 537 and is one of the great examples of how the city has gone through the mix of religions and cultures.
Basilica Cistern: Istanbul used to have several hundreds of these, all built by Romans. Romans believed that still water was clean water - opposite to Ottomans who later preferred to drink from flowing streams. This was the largest Cistern in use in the city, and is still in great shape. Walk to the end to see two Medusa column bases (one of which is sideways probably just because the pillar was too long and it did not fit vertically). Unfortunately when I visited, the Cistern had no water - and you can blame the Inferno movie (from Dan Brown's book) for the continued restorations on the Cistern.
Grand Bazaar: The hype is real. This Bazaar is a wonderful place where you can both get lost and spend a lot of money (depending on your budget of course). There is everything from carpets to clothes, but I definitely recommend you go into the center, where the antiquities in the Old Bazaar can be found. And make sure you ask for a discount - prices are never, ever, final in Turkey.
Bazaar of Spices: A smaller version of the Grand Bazaar, that is a bit more organized and focuses on spices (duh), but also worth walking through.
Galata Tower: For Galata Tower I recommend you visit early (check opening times) and that way you will avoid the line that forms outside. Although sunset probably looks incredible from up there I decided to skip it. The city does look amazing from there - and if you really want to see the whole city during the sunset, just find a rooftop restaurant/bar.
Dolmabahçe Palace: This was the last home of the Ottoman empire between the end of the 1800s and 1922. As Europe began influencing the style of the high class in Istanbul, the Sultan wanted a more contemporary home than the Topkaki Palace. It will look very European, you will have to wear plastic bags over your shoes, and they will not let you take pictures, but it's worth walking through - especially the last room that is visited. Won't give away what room that is...
Eminönü: This neighborhood is home to most of the places of interest in the list above, so you should head there first. Definitely full of tourists, but still very much local given that Turkish people are active at the Blue Mosque and the Bazaars as much as tourists are.
Beyoglu: This neighborhood is the best place to stay at. If you still do not have a hotel or room, I recommend an Airbnb in this neighborhood. It has lively restaurants, it's pretty, has somewhat of a central location in the city and is the one where I saw the most cats.
Karaköy: Down by the river, below Beyoglu, here you can grab a ferry to cross to Asia, or take great photos of Eminönü at sunrise/sunset as well. It has some good cafes, and if you walk to Eminönü you should deviate and explore it a little at least.
Balat: Located a bit north on the Eminönü side, Balat is a growing neighborhood full of cute coffeeshops and VERY colorful buildings. Great for your insta posts (tag me so I know soooomeone read this) and also to have a stroll down by the river.
Bebek: A more elegant neighborhood - easily accessible by bus, even though there might be traffic on the weekends. Here you can find great places for a typical Turkish breakfast, which will leave you full and content, and then do some shopping around.
Kadiköy: I could go on a rant about this one. And the reason is that I heard so many mixed opinions about going to the Asian side of Istanbul that I felt I needed to explore it for myself and decide. I picked this neighborhood because it seemed to have a good amount of restaurants, bars and stores to make my afternoon interesting. I must tell you that it is by far my favorite neighborhood in Istanbul, and it's because you can just walk down a street covered in restaurants, drink a beer, and then buy some great great pastries down the corner. It's buzzing with life and is definitely a must.
Hope you enjoy all the cats that will want to be pet in these streets.