Revealing: "The City Beneath the Sea": When Seaview's crew recover the diver's body in the beginning and clear seaweed from his mask, the "dead" man is blinking.

Continuity: "Escape from Venice": Nelson spins the roulette wheel. We see a close-up of the wheel slowing down. Cut back to a full shot, and now the wheel is spinning faster than ever, even though no one has touched it.

Continuity: "The Cyborg": At the end, Crane shoots the cyborg Nelson in the forehead. It clutches at its completely intact face and falls down. We cut to crew reactions and then back to the fallen cyborg - and now its head is nothing but a jumble of circuits. Were those delayed-action bullets in Crane's gun?

Continuity: "The City Beneath the Sea": Seaview is on the ocean floor investigating the underwater city. Two inserted stock shots then show it up near the surface at periscope depth. In the next shot, though, it's back on the bottom again.

Factual error: "The Price of Doom": Crane clears an Air Force jet to land at the Antarctic ice station. But the station is located on a completely snow-covered sheet of ice with no runways. How and where could it possibly land?

Revealing: "Long Live the King": One of the saboteurs sneaking into the palace keeps looking up at someone off camera. He's not watching the door he just entered by, so who's he looking at in what should be an empty corner of the room?

Plot hole: "The Phantom Strikes": The Seaview's crew have a wild shootout aboard ship, and their bullets are seen to go all the way through a 6-inch-thick hatch door. Gee, you'd think that somewhere during their military training, somebody would have taught these guys why firing high velocity weapons on a submerged submarine is a really bad idea.

Factual error: "The Phantom Strikes": The Seaview's military history computers need an upgrade. The derelict German sub is identified as a WWI ship, the U444, supposedly sunk in 1918. There were only 167 U-boats in WWI. U444 wasn't built until 1942. And the sub's design is definitely WWII, not WWI.

Factual error: "The Phantom Strikes": The derelict sub is said to have suddenly moved itself more than 30,000 sea miles from its original position. This makes no sense. The entire circumference of the Earth is only 22,000 sea miles. And if the sub had somehow circled the globe plus an additional 8,000 sea miles, there'd be no way to tell that it hadn't simply moved just 8,000 miles.

Factual error: "Turn Back the Clock": The diving bell descends to 4000 feet, where no light can penetrate and the ocean around them should be pitch black. But some strange, unseen phenomenon is lighting up the bell quite nicely for the camera.

Deliberate "mistake": "The X-Factor": Car-wreck stock footage turns the admiral's 1965 sedan into a much shorter, fatter 1950s model when it bursts into flames and rolls down the embankment.

Factual error: "Killers of the Deep": Due to the extensive use of borrowed footage from the WWII film "The Enemy Below," the 1970s crew of the renegade sub (who are not German and who wore civilian clothes in most shots) suddenly acquire 1940s German U-boat caps and uniforms.

Deliberate "mistake": "Long Live the King": The Seaview's 8 huge picture windows were a concession to design over practicality. Though they knew that such big windows could never withstand deep sea pressures, the producers wanted the characters - and the audience - to be able to see all the underwater wonders "up close." The "impossible" windows became one of the show's most popular features.

Factual error: "No Way Out": Victor is crawling around through Seaview's incredibly roomy ventilation ducts, pursued by several crewmen. But the air conditioning that's fluttering little ribbons on all the vent covers isn't, for some reason, disturbing a hair on any of their heads.

Revealing: "The Magnus Beam": Crane overcomes his guard in a fistfight by hitting him in the face three times. But if you watch closely, it's apparent that not one of his blows connects. He "strikes" the air above the man's head all three times.

Deliberate "mistake": "Turn Back the Clock": Several of the roaming dinosaur segments here are repeated 2-3 times over. They're all recycled footage from producer Irwin Allen's own 1960 remake of "The Lost World," and Allen must have wanted to get as much use out of the dino shots as possible.

Continuity: "The City Beneath the Sea": Seaview's windows form 8 horizontal rectangles in 2 rows across its bow. But the interior sets have windows that form vertical rectangles, and they're much closer together than they are in the exterior shots.

Deliberate "mistake": "The X-Factor": When the helicopter is chasing Nelson's car, re-used footage from a first season show briefly turns the otherwise color episode black and white.

Continuity: "11 Days to Zero": A saboteur on an overhead scaffold hastily sprays an X on the top of Nelson's car with white paint. In later aerial shots, the X is composed of 2 perfectly straight, thick lines stretching from corner to corner of the car's roof. No way was that X made in a few seconds with a spray can.

Deliberate "mistake": "Doomsday": The huge system and missile control boards containing the failsafe units suddenly appear on Seaview's bulkheads just for this episode. And of course, they disappear after this, never to be seen again.