Known as the city that started the “eau de cologne,” Cologne is a beautiful city in north-eastern Germany with a population of roughly 1 million people.
It is very easy to fly directly into Cologne from most countries, or you can take the regional/long distance trains/planes/buses from other cities in Germany itself.
One of the great things about Germany is its interconnected rail system, and the new bus lines that are popping up. Try Flixbus for cheap tickets in between European cities, or in and around Germany. There are others, but Flixbus is the one I have tried so far, and it was a pleasant experience. You will be a little cramped, however, because it is a standard bus seat, but my journey was clean and pleasant. Bring your passport, however, because it is required.
Things to do in Cologne: if you like techno music, there is a club scene that lasts until the wee hours of the morning. Also, you can drink open containers in Germany, which is different from the United States where opened alcohol bottles in public is mainly forbidden. High-end shopping is also good here, as there are plenty of stores with nice clothes.
There is also the Cologne Dom, which is a beautiful cathedral. You can climb the stairs to the top for a good view of the surrounding city beneath you.
Walking around Cologne was mainly what I did for hours, absorbing the sights.
I stayed at a few different hostels in Cologne the four nights I was there, but all were comfortable, if slightly smaller than normal rooms in the U.S.A.
A & O Hostel was particularly nice, because I liked the location and the friendliness of the staff at the time. The rooms were also decorated in a nice, modern way, with simple amenities.
As always, all opinions are my own.