[PC EU] Any dueling spots / guilds?

Erekon

Are there any popular spots where people regularly gather up and duel?
or are there any guilds of the sort?

fred4

Bergama wayshrine in Alik'r Desert.

Last I knew the biggest duelling guild on PC EU was called Colosseum.

The players at that duelling spot and in that guild tend to be fairly hardcore. If you are new to duelling, I recommend practicing with friends, although I assume the guild has people willing to train and give advice.