[rahimnathwani]

Sorry, wrote my comment in a hurry. I understood the joke the same way everyone else did...

- he told people he got his degree from Col*mbia (both place names are pronounced the same)

- people (naturally) assumed he meant Columbia

- the punchline reveals that it was actually Colombia

- the punchline also hints that he got his degree by buying a certificate online, rather than doing bona fide online learning

[stavros]

Ah OK, I thought you thought they said Colombia initially, and I was wondering if you found something else in it funny.

Interestingly, to me, Colombia and Columbia don't sound the same, but I'm not a native speaker and I tend to think of words in terms of their spelling rather than their pronunciation.

[titanomachy]

In Spanish they sound different. In English, most people pronounce them both like “Columbia”.

[rahimnathwani]

Right. The two being pronounced the same is essential to the joke.