The war epic Dunkirk focuses on the survival of British and French troops on the French beach in 1940. [Photo provided to China Daily]

There were no real bombs falling or a war zone nearby. But Nolan says he could still sense the tension, and his respect for those involved in the evacuation increased during the filming.

WWII has been a theme for many movies. But few in the past 50 years have told this very important chapter in military history.

"As a filmmaker, you are looking for gaps. You are looking for the stories that should be told but have yet to be told," says Nolan.

"It's a film that you can only make once in your career. You have to get it right. I want to do it in a way that is very personal to me. I try to make it a subjective, tense experience."

Thanks to such films as Inception and Interstellar, Nolan is seen as one of the world's most successful directors. Ten of his films have earned more than $4.6 billion and a total of 26 Oscar nominations and seven wins.

Nolan was also nominated for best original screenplay at the Oscars for Inception (2010) and Memento (2000).

The filmmaker has again shown his storytelling talent by penning the Dunkirk script.

"I don't want to give audiences historical or political lessons. I want to give them a connection with the characters," he says.