"eternal city" should be written "Eternal City" i.e. capitalised. That's how it is in the OED anyway.
Once the capitals are there, I'm not sure the quotation marks add anything. I think you are using them as scare quotes to indicate that you aren't responsible for coining the term "Eternal City". The capital letters already do that job so they might be regarded as superfluous.
Bear in mind that in making both these points I'm being ultra-picky!
Transports Transportation
Everyone loves to travel around the biggest and most famous cities in the world. Nevertheless, when it comes to decideing how to do it, the firsts questions that may arise are , such as "what kind of transport should I take?" or "what is the fastest and cheapest way of travelling?"
Takinge as for example the city of Rome, one can distinguish four main ways of travelling.
Firstly, the fastest way of going around Rome is taking the tube. On the one hand, other positive aspects are that it's not very expensive and it doesn't leave at specific times, therefore people can arrive at the platform at anytimes they want and find the tube. On the other hand there are some negatives aspects. Surr enough the tube is always overcrowded and it doesn't stop in every quarter.
Secondly, an alternative to the tube is the bus. It does stop in every quarter but it's always in late because of the heavy traffic jams in Rome. Sadly if one decides to take it, he you will probably always arrive late. arrive lave in every date he've had.
After that there's the taxi. Still it's very comfortable despite of the compared to the overcrowded bus or tube. Yet However it's far too expensive.
The latter last way of travelling is by foot. Rome isn't as large as London or Instanbul, so it's not unrealistic to visit it by walking. Sure enough it's the slowest way of going around the city, but it's by far the most relaxing and it's also good for your health. Furthemore it's possible to see all the beauties sides beautiful aspects of the "eternal city".