The hardest area in Guild Wars

Whatever it is, I want to try it in this holiday.
I'm fairly sure it has to be in Nightfall or GW:EN. You can define "hardest" however you think is most appropriate: hardest to kill final-boss, most balanced and synergistic enemy groups, highest level etc. Just don't take length into account; this is about the hardest, not longest to finish area in GW. If you want, you can think of it as the length of time that it took to kill that enemy group, but don't think of it as the length of time to finish the respective area... there is a significant difference.

I would really like to see what everybody says because I've completed a lot of HM and I want to move on. I don't care about the drops, I just want something challenging.

One last thing, give a solid reason for your opinion. If you're going to make a post with something like less than 5 words... please, just don't bother to write it at all.

Edit: I got Legendary Guardian (so I did all mission in HM). I'm expecting for something harder than that, so please don't give missions here. And try to limit your answer to as few areas as possible.

Gate realm torment area... the pugs just wont suffice!

I've had more trouble with the Forgewight portion of Slaver's Exile than I have with any other portion of any other chapter of the game. It's taken about 6 runs at it to find a party configuration that's reasonably effective, and I'm still fine-tuning. I get the sense I'm considerably less experienced than you, though, so YMMV.

Prophecies: Icedome, Frozen Forest, Ice Floe (all three have massive mobs)
Factions: Anywhere with Jade Brotherhood (hard-hitting balanced AoE), Silent Surf (way too easy to double/triple-aggro)
Nightfall: Realm of Torment (Overleveled, overpowered monsters that doubleaggro), Poisoned Outcrops (large mobs)
GW:EN: Everywhere HM. Not a single vanqushing or dungeon run in GW:EN I've been on yet that wasn't ridiculously harder than the NM equivalent. Prepare to have your feelings about how you can PvE ripped and torn into thousands of tiny pieces. Oh yeah, Shards of Orr NM is worse than Slaver's IMO.

I Vanquished Joko's Domain in HM the largest area to vanquish or so guild wiki says, it wasn't really really hard, but it required me and another guildie to spend 4 Wintergreen CC's and 7 Pumpkin Cookies which is a first because I haven't actually had to use them in awhile.

Couldn't agree more on these. Shards of Orr is incredibly annoying.

I found a solution to NM Shards in, IIRC, 3 tries. I had no trouble at all with the first two Slaver's subdungeons, but it's taken 6 tries at different builds/party configurations to get something that even sort of works for Forgewight's dungeon. Like I said, though, it may just be me.

As to HM vanquishing in GWEN, I thought Magus Stones was pretty easy, but it's one of the few I've done.

Gate of MAdness PUG NM or HM
Getting a group without any idiots there is almost next to impossible

Arbor Bay has more mobs than Joko's Domain, but I think it takes less time to do.

Sunqua Vale.

HM Joko's Domain or similar desolation area...Cavaliers tend to be bit annoying without good shutdown skills.

get the captured son quest and do it in HM, otherwise - D-drift HM

HM vanquishing Tahnakai explorable by actually killing everything.

Interesting thread. In fact, it's really useful to the designers.

Could you include some notes about what makes the area/quest/mission difficult, and whether you think it's too difficult, or just nicely challenging?

Trying to fight from Beacons to droks with the henchmen they provide. Low level and not a max party (Not heroes or humans only you and Hench)

Total craziness

i tried destruction's depths in HM and got my ass wrapped, signed, stamped, and mailed to me by the disk of chaos. otherwise, not terribly hard in HM, but the final boss is BEASTLY. especially for me, playing a ranger -.-

Awakened in HM, when you're out of a Junundu. I need to go back there now that I've set up my team with paragons and physicals, because casters just didn't cut it.

Ice Dome and with its infamous "You die, you respawn and die as soon as you respawn" res shrine. (did this get fixed?)

And the fact that they managed to squeeze SOOOOO many bad guys in a tiny area.

Prophecies

Ice Dome
Ice Floe
Ascalon Foothills / Dragon Gullet HM (one shot ->cya)

Factions

Boring Kurzick forest keepers (gonna need Vanquish.. sounds like fun)
Jade Brotherhood spots in HM, can be a pain

NF

Torment is kinda annoying (domain of fear especially)
Kourna maps with packs of scribes in HM, especially Kodonor Bonus (monk heal boss + elite scribes + priest, cant figure something out)
Awakened in HM: pain in the a** as well

GW:en

HM, way too boring
sacnoth valley, burning spirits, totally unplayable imo, dark, spikalot fellas, crappy view when using devourer and all that in the middle of annoying trees.

Mursaat and Imps in Ice Floe, now that is a classic challenge.
Mind you I have not done it a long time and have not been there since heros were introduced.
But I remember painful times there trying to map it and running my level 10 Necro to Marhan's Grotto to get his yet not updated at the time Tormentor armor (ahh the good old days)