The new film "Night at the Museum: Secret of the Tomb" is the third and last film in the series' franchise, and it coincidentally became the last movie that Robin Williams and Mickey Rooney would appear on screen.

"It was very poignant," says director Shawn Levy. "I think the movie expresses a certain love for these characters."

In this latest installment, the tablet starts losing some of its magical power. Guard Larry Daley, played by Ben Stiller, realizes he must travel to the British Museum in London to figure out how to fix it. 

"Larry Daley's farewell to this museum family was also my farewell to my museum family," says Levy.

Levy says this series brought him a lot of joy because of the ability to see the inner-workings of some of the world's most esteemed museums up close.

"Ben Stiller was reminding me," he says, "that when we were filming a scene in the great court of the British Museum, before an actor does a scene there's always a start mark where they begin walking from. In the case of that night in the British Museum, their start mark was literally the Rosetta Stone."

 But by far, Levy says he will miss working on this series and actors like Robin Williams.

"To get to watch that kind of inspired, truly rare -- like once a generation kind of talent -- up close, it's a privilege," he says, "but I'll treasure that more now that he's gone."