This summer marks 20 years since the release of Band of Brothers, HBO’s ground-breaking and award-winning World War Two miniseries.

Created by Steven Spielberg and Tom Hanks, and starring Damian Lewis, Donnie Wahlberg and David Schwimmer, the show follows US paratrooper battalion Easy Company and their exploits during the conflict.

Most of the filming of the 10 hour-long series took place on a mammoth set at the old Hatfield aerodrome, the former home of the de Havilland Aircraft Company.

Here’s nine things you might not know about the making of Band of Brothers.

1. It cost $120 million to make

Welwyn Hatfield Times: Band of Brothers is still the 10th most expensive TV series of all-time.Band of Brothers is still the 10th most expensive TV series of all-time. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

When discussions first began about making Band of Brothers, it quickly became clear that the required budget was simply unheard of for the time.

The miniseries cost a total of $120 million to make, with each episode costing an average $12 million.

Two decades on, that colossal budget still sees Band of Brothers ranked as the 10th most expensive TV series of all-time, beaten out by the likes of Game of Thrones, The Mandalorian and The Pacific – Hanks and Spielberg’s follow-up Second World War series.

Speaking to the New York Times in 2001, Hanks admitted that HBO were taken aback by the budget, saying: “I'm not saying they didn't bat an eye. Oh, they did bat an eye. But the reality is this was expensive. You had to have deep pockets. And HBO has deep pockets.”

2. 11 different locations were created on set

Welwyn Hatfield Times: Scenes of 10-part war drama Band of Brothers were filmed on sets built on the former Hatfield aerodrome.Scenes of 10-part war drama Band of Brothers were filmed on sets built on the former Hatfield aerodrome. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

The former Hatfield aerodrome is now home to the University of Hertfordshire's de Havilland Campus and a number of other buildings, but back at the turn of the millennium it became Second World War battlefields.

A 12-acre village set was created for filming, and this was continually modified throughout production of the show for scenes based in 11 different locations including England and Holland.

It dwarfed the set of another Spielberg war classic, 1998’s Saving Private Ryan, as revealed by Hanks in The Making of Band of Brothers documentary.

“It's about five times bigger than we had on Saving Private Ryan,” he said.

“We're in Auburn, and Upottery in England, we're in France, Normandy; we're in Holland, we're in Bastogne... we're all over the place here.”

3. One of those sets was an indoor forest

Welwyn Hatfield Times: A shot from episode 7, titled Breaking Point, that was filmed in the indoor forest set.A shot from episode 7, titled Breaking Point, that was filmed in the indoor forest set. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

The Bastogne and Breaking Point episodes of the series see Easy Company fight off the German counter-attack during the Battle of the Bulge, but the forest set for part six and seven was actually made indoors.

Belgium’s Ardennes Forest was recreated in a hangar at the aerodrome using hundreds of real and fake trees, with the latter designed by the special effects team to imitate those felled by explosions in the heat of battle.

It also took the crew four weeks to cover the indoor forest in man-made snow, which was created using paper and polymers.

4. Actors took part in a gruelling 10-day boot camp before filming

Welwyn Hatfield Times: The boot camp left a lasting impact on some of the actors.The boot camp left a lasting impact on some of the actors. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

To prepared the cast for the filming of Band of Brothers, a gruelling 10-day military boot camp was put on, and it left a last impact on a number of those involved.

Run by ex-Marine and Vietnam War veteran Captain Dale Dye, the camp was designed to ensure accuracy during production and give the actors a realistic experience of combat to help them portray their roles.

The rigorous 18-hour days were crammed with physical activity and military drills, including parachute jump training from 40ft up.

Recalling the boot camp, Matthew Settle, who plays Ronald Speirs, said: “The worst night was sleeping outside in these sleeping bags that if you got in them, it was colder than being outside.”

Frank John Hughes, who portrays Bill Guarnere, continued: “I saw guys taking off their socks to give to other people to stay warm, and you would take your jacket off to give to someone else.”

It took a physical and mental on some of the cast too, with Donald Malarkey actor, Scott Grimes, remembering: “You hit walls in boot camp. You hit these personal mental and physical walls that you have to go over.

“There were guys the first night of boot camp that cried themselves to sleep.”

5. Real guns were used - and lots of ammunition too

Welwyn Hatfield Times: 14,000 rounds were used each day during filming for the show.14,000 rounds were used each day during filming for the show. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

To give Band of Brothers a realistic feel, real Second World weapons were used by actors and extras.

More than 700 authentic guns, including the American M1 Garand rifle, M1A1 Thompson and German MG 42 machine gun were involved in filming, while the props department created hundreds of foam weapons.

A number of original aircraft such as the P-51 Mustang and C-47 Dakota also appear in the series, while a mobile German Panzer and Tiger tanks were built on top of car chassis by the crew.

There was plenty of ammunition used too. Around 14,000 rounds were fired each day during filming, more than was used in the entirety of Saving Private Ryan’s production.

6. More than 10,000 extras took part in filming

Welwyn Hatfield Times: Damian Lewis as Richard D Winters and Ron Livingstone as Lewis Nixon in the first episode of Band of Brothers.Damian Lewis as Richard D Winters and Ron Livingstone as Lewis Nixon in the first episode of Band of Brothers. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

Lewis, Wahlberg and Schwimmer were among the stars of the show, while up and coming actors such as Tom Hardy, Michael Fassbender, Simon Pegg and James McEvoy also appear, but it was the extras that formed the backbone of the series.

More than 10,000 of them were used during the filming of Band of Brothers, with many of those appearing in scenes filmed at the giant set in Hatfield.

With such a large number of actors and extras involved, clothing them proved quite the task for the costume department, with 2,000 German and American military uniforms used, as well as 1,200 civilian outfits.

7. Actors were scared during filming

Welwyn Hatfield Times: Eion Bailey (left) portraying Brian Webster in Band of Brothers.Eion Bailey (left) portraying Brian Webster in Band of Brothers. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

The realism that Band of Brothers portrayed on screen for viewers also came across to the actors during filming.

In The Making of Band of Brothers documentary, actor Eion Bailey, who plays Brian Webster, recalled a scene in which he feared he would be ‘shot in the head’.

Remembering filming for episode five, titled Crossroads, he said: “There's a scene where we were at a crossroads and we surprise a bunch of Germans in an apple orchard.

“There’s about 100 Germans running away and then they start turning and firing at us. Another German platoon comes storming down this hill and starts attacking us.

“All of a sudden this riverbed just explodes. Boom, boom, boom, all the way down and the ground is shaking.

“I remember when I was reloading and I was trying to jam my clip in, but I was having trouble because my hands were shaking. I was thinking ‘I’m going to get shot in the head right now while I’m not looking and everything is going to turn to black’.”

8. The D-Day take off scenes were the most challenging to film

Welwyn Hatfield Times: Damian Lewis and David Schwimmer during episode one, Currahee.Damian Lewis and David Schwimmer during episode one, Currahee. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

Band of Brothers was an ambitious project, but director Phil Alden Robinson remembers the most testing part was filming the D-Day preparation scenes that appear in episode one, titled Currahee.

In The Making of Band of Brothers, he said: “From a physical production standpoint, the most challenging scene was taking off for D-Day.

“We had hundreds and hundreds of extras, each of whom had to be accurately equipped and uniformed. It was a tremendous feat of co-ordination.”

9. The final day of filming was ‘more like a wake than a celebration’

Welwyn Hatfield Times: There was a sombre atmosphere among the cast when filming wrapped on Band of Brothers.There was a sombre atmosphere among the cast when filming wrapped on Band of Brothers. (Image: ©2001 Home Box Office, Inc. All rights reserved. HBO® and all related programs are the property of Home Box Office, Inc.)

When most film or TV productions wrap, the cast and crew celebration their exhaustive work. But the bond formed while filming Band of Brothers left a sombre atmosphere at the close of filming.

In An Extra's Life - On the set of Band of Brothers, a short film shot by extra DC Alden, he describes the emotions of filming ending.

“There were rumours of reshoots, a Pacific Band of Brothers being shot in Hawaii and we all hoped that somehow we’d be involved,” he said.

“That last day, the mood was more like a wake than a celebration.

“Some of us shook hands and vowed to stay in touch. Others we never saw again.

“For some, Band of Brothers was just a pay cheque. For the rest of us, the happy few, the extras who worked through the summer heat and the winter rain, it was an experience we will never forget.”