The best flight is probably an Avianca from Madrid. You will need to connect to it however through a separate ticket which may not be in business but it's just a 2 hour flight.

The MAD->BOG->MAD is about $3123 on July 23rd-Aug 23rd.

Avianca is a pretty nice airline. It's not in the league of Asian airlines but it's a comfortable 10 hour flight.

Cheaper than that originating in Madrid is Condor for $2847 but it's a terrible journey: MAD->FRA->SDQ->PTY->BOG.

American Airlines at $3274 with a stop in Dallas. Also originating from Madrid.

In general tickets from Madrid to South America will be cheaper than other European origins because there is a fair amount of competition between carriers originating from there. It's pretty much the only European hub well connected to South America. I know this because I just recently flew from Madrid to Santiago (Chile) and researched all these options about .... 15 days ago.