Re: potato potato
Frequent misspellings aside, Colombia has been officially spelled like that since Colombian independence, at least in the UK already since its predecessor state (nowadays known as Gran Colombia) was officially recognized in 1825. There are several official documents from both USA and UK online referring to Colombia dated over a century ago, but I can'ẗ find any using "Columbia". (Feel free to point counterexamples to me.)
Some other languges, however, use the "u" form, e.g., German "Kolumbien", Finnish "Kolumbia".