Time travel can be messy. It can also be the core of a very entertaining story. In Marvel Comics, time travel has very definite rules. When traveling back in time, one goes to an alternate past that diverges the instant the time traveler arrives. When traveling into the future, the traveler goes to one of many possible futures.
Editor Mark Gruenwald put the rules into writing. He established that paradoxes couldn't exist because of the nature of Marvel's laws of time travel. The first heroes to travel through time may not have realized this until much later. Even in the present, less intelligent characters don't completely understand how time travel works.
10 Blonde Phantom Was Kidnapped To The 30th Century
Blonde Phantom #21 (1949) By Al Gabriele & Harry Sahle
In Blonde Phantom #21, Louise Grant, the Blonde Phantom, was at a "future fair" exhibit by an eccentric millionaire, Mr. Kall. Mr. Kall was from the future and used the fair to kidnap many people from the past and take them to the 30th century. There, the future people put the kidnapped people from 1949 in a zoo for an exhibit on primitive humans.
The Blonde Phantom escaped and confronted the leader of the 30th-century world. She overpowered him with hypnosis and her stronger will. She forced him to free the kidnapped people from 1949 and send them home. She also took him back as her prisoner.
9 Captain America Chased A Robot Through Time
Captain America #73 (1949) By Ken Bald
It's a commonly-known retcon that the Captain America in stories published after WWII is not the original. That means that this particular Captain America is a separate hero from Steve Rogers. He does hold the notoriety of being the first Captain America to travel through time, drawn by Golden Age artist Ken Bald.
Cap and his friend Alan Tremont chase an evil doctor named Wolf Turber who's abducted Alan's sister. They end up chasing Turber through time. Turber is looking to conquer another time and rule it with Alan's sister as his queen. Captain America overpowers Turber in the far-distant future, revealing him as a 31st-century robot.
8 Mister Fantastic, Human Torch, And The Thing Created The Legend Of Blackbeard
Fantastic Four #5 (1962) By Stan Lee, Jack Kirby, Joe Sinnott & Stan Goldberg
The first time-travel story of the Silver Age introduces the most used method of time travel in Marvel Comics. Doctor Doom's time machine is the invention that marks him as one of the leading intellects in the Marvel Universe.
Doom Captured the Invisible Girl and used her safety to force the rest of the Fantastic Four to go back and retrieve Blackbeard's treasure chest. During the trip, the Thing's disguise created the legend of Blackbeard before Doctor Doom retrieved the trio. Reed Richards outsmarted Doom, replacing the jewels inside the chest with chains.
7 Thor Chased Zaarko, The Tomorrow Man Using The Power Of Mjolnir
Journey Into Mystery #86 (1962) By Stan Lee, Larry Lieber, Jack Kirby & Dick Ayers
Zaarko traveled from the year 2262 to steal an experimental cobalt bomb. He flees from Thor, who manages to only chip off a small piece of metal from Zaarko's time machine. Thor summons an audience with his father Odin for the power to chase Zaarko through time. Odin instructs him to use the power of his hammer, Mjolnir to trace the piece of metal back to its source.
Thor arrives in 2262, where Zaarko rules like a tyrant with the only weapon on Earth. Thor uses a decoy to occupy Zaarko, so the Thunder God can get an advantage in the battle. Zaarko flees, threatening to drop the cobalt bomb. Thor crashes the ship, reclaiming the bomb.
6 Iron Man Went Back To Meet Cleopatra
Tales of Suspense #44 (1963) By Stan Lee, Robert Bernstein & Don Heck
Stan Lee, Robert Bernstein, and Don Heck tempted Tony Stark with history's greatest beauty in Tales of Suspense #44. As Tony Stark went back in time as the Mad Pharaoh's prisoner with his mystical chariot charm. He escaped soon after arriving and donned his Iron Man armor and drove off Roman soldiers. He then protected Cleopatra's barge from a Roman Galley.
Cleopatra tasked Iron Man with defeating the returned Mad Pharaoh. In doing so, the villain fell on a sword. Iron Man turned down Cleopatra's offer to stay in the past with her. Using the Mad Pharaoh's charm, he returned in 1963.
5 Invisible Woman Journeyed With the Fantastic Four To Face Pharaoh Rama-Tut
Fantastic Four #19 (1963) By Stan Lee, Jack Kirby, Dick Ayers & Stan Goldberg
Chasing a cure for Alicia Master's blindness, the Fantastic Four returned to Doom's castle to use his time machine. They journeyed back to Ancient Egypt and found it ruled by the time-traveling Pharaoh Rama-Tut. He came from the year 3000 in a time machine built from an ancestor's plans.
Rama-Tut enslaved the heroes, taking a romantic interest in Invisible Woman. When the team broke free, Rama-Tut fled back to his time machine. Unfortunately, Doom's time machine couldn't transport the radioactive cure for blindness.
4 Doctor Strange Journeyed To Save Cleopatra From A Wizard
Strange Tales #124 (1964) By Stan Lee, Steve Ditko & George Bell
Doctor Strange found a hooded woman roaming the streets, mesmerized and unresponsive. Investigating, he determined that she was from some point in the past. With the aid of his mentor, the Ancient One, Doctor Strange traveled in his astral form back to Ancient Egypt.
There Strange discovered an evil sorcerer intent on overthrowing Cleopatra. Doctor Strange defeated this sorcerer, but almost became stranded in time. Rescued by the Eye of Agamotto, Strange returned Cleopatra to her own time. Making no reference to Iron Man's encounter with Cleopatra, Lee and Ditko brought this tale to readers.
3 Immortus Took Captain America And Rick Jones To 18th-Century London
Avengers #10 (1964) By Stan Lee, Don Heck, Dick Ayers & Stan Goldberg
Immortus struck a deal with Baron Zemo to capture an Avenger. Immortus lured their young ally, Rick Jones, into a trap, imprisoning him in the Tower of London in 1760. Captain America and the Avengers arrived to force Immortus to free Rick. Immortus abducted Captain America to the 18th-century Tower of London.
Captain America overpowered Immortus's medieval soldiers and freed Rick Jones. He returned to the Avengers to help defeat Zemo, Enchantress, and the Executioner. The Enchantress cast a spell, reversing time by a few days, so they could avoid this humiliation.
2 Kang Took Hawkeye, Quicksilver, And Scarlet Witch To The Future
Avengers #23 (1965) By Stan Lee, Don Heck, John Romita & Stan Goldberg
The Avengers were without Captain America who'd left the team feeling that he had failed as their leader. It was at this moment, depicted, that Kang abducted the remaining members. He took Hawkeye, Quicksilver, and the Scarlet Witch to the future where he was conquering the kingdom of Princess Ravonna. Kang hoped his defeat of the Avengers would persuade Ravonna to marry him.
Captain America taunted Kang to join his teammates. Together, they battled Kang despite overpowering odds. Their defiance gave Ravonna the resolve to resist Kang. In the end, Kang's own commanders betrayed him. Kang allied himself with the Avengers to save Ravonna's life.
1 Hulk Was Transported To A Post-Apocalyptic Future
Tales to Astonish #75 (1966) By Stan Lee, Jack Kirby & Mickey Demeo
In the Silver Age, the U.S. Military hounded the Hulk. After getting a weapon from the Watcher, he ran afoul of the army building Banner's latest weapon, a massive "T-Gun." No one realized that it was a means of time travel.
With his intellect heightened by the Watcher's weapon, Hulk headed to the White House, guided by Rick Jones's thoughts. The T-Gun sent the more intelligent Hulk into the future. There he found a ruined Earth where futuristic soldiers attacked him, some led by Thor's foe, the Executioner. An extended story arc with Hulk battling against both armies began.