Maguuma Explorer - 166/167, 100% map
Do you have the Shimmerstone Cave in Sparkly Fen? That was the one I was stuck on, as I initially assumed it was just a big rock/mountain in the middle of it all based on the brown patch it covered on my map.
http://wiki.guildwars2.com/images/f/f3/Sparkfly_Fen_map.jpg
Oh my God, thank you so much. That was it. I have assumed the same, I was even checking my map with this one on wiki and didn’t notice it. Thank you once more.