Gibbs clearance is so high he gets to see the dead aliens at Area 51.

It was a joke that went round NCIS, but it was fundamentally true, Abby once asked Gibbs how far his clearance went, the only answer she got was "all the way".

Tom Morrow was the first director to extend Gibbs clearance, did it as Gibbs took over what would later become Leon Vance's OSP division. Gibbs needed access to high levels of security to do his job, and if he was honest it was easier to extend Gibbs Clearance than have the man threaten every mission by grumpily shouting down secure phone lines when he couldn't access the intel he needed.

This somewhat set a precedence, whilst banging heads with the CIA in Moscow, he'd been allowed access to their most secure files. Much to his amusement, and relief, at the end of his deployment that clearance was never revoked.

As the head of the MCRT Navy Yard, Gibbs became answerable to the Director only, it amused Tom that Gibbs had as high clearance as he himself, making Supervisory Special Agent LJ Gibbs, defacto second in command of a Federal Agency.

When the SecNav had some reservations about Morrows command of the agency, he came to Gibbs. His clearance climbed higher, on a par with SecNav, the day Morrow discovered Gibbs clearance was higher than his, was the day the jokes started.

9/11 was the day the joke became reality, for most Federal Agents their clearance was revoked or at least demoted. However Tom Morrow had been on holiday and Gibbs had been acting Director. In line with other Directors his clearance had been extended "all the way" he heard the jets over Pennsylvania, locked in the MTAC he watched with horror as the events unfolded, and was in almost constant video conference with not just the Defence Secretary of the US, but those of most of their allies as well.

When Morrow returned the next morning, Gibbs returned to the safety of his own desk, the relative anonymity of a small team in a tiny agency. It wasn't until the following Christmas he realised he still had the highest level of Security Clearance. On a case involving a top secret naval operation and a dead Petty Officer who wasn't, he thought he'd bypass Tony and Abby and do some sleuthing of his own, the more he searched the more he expected to come across an Access Denied message. Having found the information required, he decided to see how far he could push it.

Gibbs never did it again, it wasn't the phone call asking what he was doing, it wasn't the files and files of the Presidents private life he'd scrolled through. It was the file he saw just before he turned off the computer, went home and drowned himself in a bottle of Bourbon. Something's you're best not knowing, something's were more terrifying than Tony's fear of Vampires, or Abby's fear of intelligent Sharks. There are things behind the wall of civilisation no man wants to peak behind.

So when Tony joked about Area 51, and aliens, Gibbs smirked. If only it was Little Green Men….