Is it practical to become an airline pilot in order to travel internationally? I am a person with very diverse interests and a lot of life goals I want to achieve. One of them is becoming an airline pilot (just working as one for a year or two) and the other is traveling the world.

I would like to combine two goals in one, that is becoming an airline pilot after I finish college and travelling the world at the same time, i.e. flying intercontinental flights.

So, my question is basically this: Is it possible to learn to fly and become an airline pilot within about 3 years (let's say age 20-23), then immediately get employed as an airline pilot and fly intercontinental routes (even as a co-pilot)?
No, this is not a good idea, and No, it is not possible finish your education at 23, and then get employed as an intercontinental airline pilot. 

It seems you have a distorted idea of what an airline pilot actually does. An intercontinental airline pilot usually spends just 24 hours at the layover destination. Much of that time is spent sleeping to recover from the fatigue of the long haul flight and sleeping to prepare for the next long haul flight. Not much time for sight-seeing.  

The first requirement for becoming an airline pilot is a love of aviation and aircraft.  Most airline pilots today have been passionate about aviation since an early age. 

You will never be successful unless you are passionate about aviation due to all the roadblocks and hardships you will have to overcome in order to reach your goal. 

To say that you only want to do it for 1-2 years is proof enough that you don't have what it takes.