You have to find the password to the terminal left behind by the Keller family. There is a great guide on gamefaqs that describes the process in detail. http://www.gamefaqs.com/ps3/939932-fallout-3/faqs/55585
You have to go through the offices and when you get all the way around to the upper depot door, open it and cross the hall, open that door and you will see it on the wall at your left. You can see the bunker door from the switch.
The FatMan you are talking about is the MIRV. It's in the national guard depot, and to get in you will need to find all of the Kellar family chronicles.
small guns bobble head in the National Guard Depot - National Guard Armory and the sneak bobble head in the Yao Guai Tunnels - Yao Guai Den good luck :)
There is an unmarked quest involving the Keller family. You have to find all Holotapes which gives you a code to enter an armoury in the national guard depot. Hope this helps.
you have to get all the Keller family transcripts and go to the natianol guard depot and open the armory
i know that the science bobble head is in rivet city, dr. lee's labsneak is in the Yao Guai Tunnels - Yao Guai Densmall guns is in the National Guard Depot - National Guard Armoryintelligence is in Rivet city - Science LabScience - Vault 106 - Living Quarters
that is completely based on your own opinion but arguably the best weapon in fallout 3 is the "experimental MIRV" which shoots 8 mini nukes at a time, which can do huge amounts of damage. you can get this weapon by getting all the Keller family holo-tapes, and going in the national guard depot.
The experimental MIRV is located in the National Guard depot. You cannot enter the room until you have all five Keller family transcripts. There will be a glowing one in there as well. Be sure and save before you fire as it will most likely harm you or your followers if you have any.
at home depot or lowes
Canadian National Depot was created in 1914.
The phone number of the National City Depot is: 619-474-4400.
The address of the National City Depot is: 922 W 23Rd St, National City, CA 91950