The first greeting that American bomber formations had on the way to a target in Europe was from anti-aircraft "flak" batteries along the North Sea and English Channel. The work "flak" is a Americanization of the German word Fliegerabwehrkanone. Current US slang for these types of guns is AAA - Anti-Aircraft Artillery.
One such battery that operated near the Zunder Zee in Holland (Netherlands) was nicknamed "Cross-Eyed Charlie" by members of the 734th Sqd in the 446th Bomb Group 20th Wing 2nd Air Division which Bill Washburn was in.
Flak Greetings Over Bremen Germany 
Bill Washburn took this photo
from the right waist gunner position in his Consolidated B-24-J Liberator heavy
bomber in January 1945 over Bremen Germany. This was scanned from his original
print given to him by the photo lab after the censor's cleared it.
Note the three flak bursts in the
left side of the picture.
The two smoke trails are from the
special bombs dropped by the lead bomber so that trailing bomb groups
toggle theirs bomb at the same point in space. This is why the lead
bombadier had to be REALLY good - else the whole group would miss the
target.
The Air Force
Museum has it labeled as being taken over Tours France in their museum.
The curator suggested I use the river and match it up to prove it -
and I did - perfect
match of the river at Bremen. I used Google Earth® to place the
vantage point at 23000' - the normal high bombing altitude for B-24s.
Most of the forests are even still there! I colored the river a darker
blue so it would stand out more on the Google® image.
I scanned this in from his
original print he got back from the base photo lab. It still
has the censor stamps on the back as does all of his prints. He used
an Argus C3 to take the aerial photos.
It seems
that he could get film by writing directly to Kodak and they sent him free film
- but he could only turn in the film for developing at the base lab. They developed
his negatives and printed them - but only gave back prints to him that cleared
the sensors and the Army Air Force kept the negatives. This negative
is now in the National Archives - and it has fingerprints on it. When they print
it they crop the image!
The name was an affectionate compliment since this battery caused damage to planes every time they went over that area. He never missed damaging at least one plane.
A new book out that examines the idea of bombing cities to kill civilians was published March 7. Written by A C Grayling it uses the above picture on the dust jacket and inside. However, it labels them as British Avro Lancasters! I bought the book and plan to read to see what other mistakes he has in there.
Among the Dead Cities:: The History and Moral Legacy of the WWII
Bombing of Civilians in Germany and Japan
He took these other pictures with the same Argus C3 with a UV filter on the lens. He eventually became one of the official photographers on missions (in addition to his combat duties) and they gave him military type cameras to take photos during bomb runs to get strike photos during the drops. The strike photos are from the Air Force Cameras.

Bomb strike image taken during B-24 raid on a German rail yard
by the 446 BG(H)
2nd Air Division, 8th Air Force.
He kept taking photos with his own camera however. The back of the prints that I scanned in still show the censor stamps and initials clearing them for release.

Bill Washburn and the Crew of the 'I Hope So!'
Bill completed 13 of 17 missions in a B-24 Liberator as flight engineer and top turret gunner. Never bailed out, never shot down.
"I Hope So" was decommission after the war and ended up in Arizona for scrapping.
This info is available on the 446th BG (H) web site Bungay Buckaroos.
Bill died in October of 2004.
The view of destruction of a target from 20 to 32 thousand feet is vastly different than seeing it on the ground. A site that shows before, after and now photographs is Third Reich in Ruins.
This link at this site, the 303rd (H) Bomb Group Association , has pictures showing what the standard bomber box formation is supposed to look like.
"I served as a fighter pilot in the 15th Air Force, 52nd
Fighter Group, 5th Fighter Squadron. I flew my combat missions in the North
American P-51 Mustang."
"It was during a bomber mission when I saw the most shocking sight my eyes
had yet seen. I was flying Red-Two, the wingman for the squadron leader. We
were patrolling parallel to the side and above a bomb wing when it started
its run. I noticed an exceptionally large and accurate burst of flak exploding
directly in front of the lead aircraft."
"The altitude of the burst was precisely calibrated. ... I thought, oh, that
next burst is going to hit right in the middle of them. Within seconds, the
next burst did exactly that. ... That poor B-24 did a sudden quarter roll
to the left, away from the formation ... and then in a blazing explosive flash,
it simply disappeared."
"No parachutes, no traces, other than a few small smoking falling pieces.
Nothing. Gone. Ten men, gone. I felt as if someone had hit me in the pit of
my stomach. I was stunned. I could visualize in my mind the young pilot and
his crew, who only seconds before were just as much alive as I was. And now
there were no traces left of them or their aircraft. They no longer existed."
"I would see similar scenes of disaster several times, and I always felt a sense of personal loss when it happened, but that first B-24 is the one I'll never forget."