Magical and mundane security for a underground base

[Friend of the Dork]

Hello

The PCs in my game are going to infiltrate/attack their old headquarters in a govermental organization. They are about 10th level and can be expected to have a lot of magical tricks up their sleves, so most mundane security is going to be useless.

The owners of this underground base have access to resources from the government (Empire), from a secret organization with access to rare and exotic magic (inlcluding golems), and they have some forwardning that the PCs will be coming, and what their abilities are.

So given a budget of say, a couple of hundred thousand GPs, what can be reasonably installed? The magical and mundane defense can't interfere with day-to-day activies, and should be layered with lowest level first, and higher level as you go further down. They can have spells or items made by 15th level spellcasters as the absolute max.

The PCs have the advantage of knowing about the surface security, which includes human guards, locked iron doors, corridor with arrow slits, and potentially some Alarm spells. This part needs no defence against Invisibility or Blink.

The second part includes offices and armories. Security here should be able to prevent mid level magics such as invisibility, blink, minor illusions, as well as well secured by Arcane Locks and some potential magical or mundane traps.

The third part needs the top level of security. Ethereal foes should be stopped by Force effects or Ethereal monsters, main door should be very hard to impossible to get through without proper access, and the areas can have a myriad of magic or mundane traps, golems, creatures with Scent, and other tough enemies, including spellcasters.

Spells I have considered:
-Guards and Wards: Affects everyone, so not really useful.
-Glyphs: Only for specific warded doors - base damage is not that useful, but Invisibility Purge, Glitterdust, or even something that alerts nearby foes could.
-Antimagic Field: Probably too expensive or difficult to have up all the time
-Mages Private Sanctum: Used for briefing rooms and high-level officers throughout.
-Wall of Force (Permanent), or Symbol of Sealing: Useful at some doors, but ehtereal creatures can go around. Mainly to prevent one from getting throuhg a main door by bypassing conventional locks or Blink.

Anything obvious I left out? Any other good intrusion countermeasures? It can be as sci-fi as you want, as long as it can be barely explained with PF magic.

[Claxon]

May I suggest that "they" use that money to create several, possibly even layered, permanent greater demi-planes. They can make the demiplane in whatever shape they desire and can make them antimagic/dead magic to their hearts delight. Fill with golems and high DC locks etc and you can make the place virtually impenetrable. Sprinkle in a few mundane traps.

Bingo bango, you're players will have a hard time cracking this fortress.

[Suthainn]

Lead pipes, full of running water embedded in walls, floors, ceiling etc should foil almost every sort of scrying or locate spell, permanency wall of force over the inside walls prevents ethereal, Dimensional Lock would prevent ethereal creatures from returning to the material in the protected area. Forbiddance whilst expensive and requiring all the npcs who enter be the same alignment is also an excellent way to stop ethereal travel in or out of an area. Hold Portal at a high CL can also work well on doors.

Guards with perm. Arcane Sight and ones with See invisible behind heavy, warded doors that require a password before opening, whilst it introduces its own problems, you can also have them remain out of sight and not look at the person giving the password to avoid charm effects (though it does mean that mind reading on previous guards who did know the password is an issue).

[Ascalaphus]

Lots of sensors to warn the guards if an attack is underway, so that the entire base can respond, instead of the PCs facing room after room of level-appropriate encounters. If you have the fight the whole dungeon at once because you didn't manage to quietly take out a trap or guard...

Also, if the things in the base are truly important, you have to accept that good security WILL get in the way of maximum office efficiency. But getting raided is even worse.

[Friend of the Dork]

Hmm, using demi-planes might be a bit off the scale of this facility, although I might do that for the final stronghold of the BBEG of the campaign.

Lead lining in doors and some walls is not too expensive, so this one's a god, if nothing else it blocks detect magic, detect thoughts etc. Not sure it block scrying though?

The problem with having too good initial security is that the PCs would know about it (passwords etc.) and thus have no problem getting in. Besides in my plot there is actually two bases - one is the PCs old organization (elite police force like FBI) the other one below is a major conspiratorial organizaton and their mercenaries (think Illuminati, or the Republican party). The initial levels will therefore be easy to infiltrate, but getting down to the area that has been closed off to them forever requires a password they have to get above, and down there are some dangerous enemies, including those with see invisibility.

Sensors fit, but what spells? Just Alarm? Some areas like gateways will have Permanent or resetable Alarm that always goes off, so that a guard can check who it is and turn a lever to allow passage.

Inside the areas will be "alarm buttons" of some sort that can be triggered by the guards to summon all others in their location, and alert the rest of the base. Fighting the whole dungeon isn't as bad as it sounds though, as most will be low-level minions easily dispatched by the PCs, and some of the tougher enemies will be instructed not to leave their posts.

The important parts of the base are two fold: First is a surveillance room with Crystal balls - which is also what the PCs are after. At the lower level is also:
-Crystal Ball with Telepathy (which made the PCs really want to attack this base)
-Laboratories working on magical constructs
-Holding pens for magically bred abberations or other monsters
-large armory with magical weapons and armor, including a cache of rare mithral.
-holding cells to secure dangerous prisoners (possibly Antimagicked or at least Planar locked
-command senter with said crystal ball, maps, written plans etc.

[Suthainn]

Lead blocks scrying so they should probably end up going in mostly blind to what's inside.

Quote:

Lead sheeting or magical protection blocks a scrying spell, and you sense that the spell is blocked.

http://www.d20pfsrd.com/magic#TOC-Divination