Built following the Human-Covenant War, the UNSC Infinity is one of the largest manmade spacecraft constructed in the Halo Universe. At 5,694.2 meters in length, the Infinity is over three and a half miles in length, and half a mile thick. This colossal spaceship is larger than some cities.

Leviathans from Starcraft are essentially capital ships wielded by the Zergs. Each one dwarfs just about every other major ship in the Starcraft universe, save for the destroyed Arkships. Leviathans are roughly the size of a moon each, making them far larger than just about any spaceship you'd reasonably want to see fly into battle.

Not to be confused with the James Cameron film, Avatars from EVE Online are titanic ships, each one over 155 million square meters. These are titanic flying tanks you wouldn't want to run into in a fight. More horrifying than that, they're relatively common in this universe.

The Erebus is another Titan ship from EVE Online. Again, this massive thing is gargantuan, Though slightly smaller than an Avatar, the Erebus is longer and arguably more dangerous, depending on who is steering this gigantic ship.

The Andonyne Spirit is a Forerunner Dreadnaught ship from the Halo Universe. At over 10 thousand meters in length, it is one of the longest ships ever constructed for a sci-fi universe.

Destiny's The Traveler is one of the most iconic gargantuan ships ever constructed in a video game. This moon-sized ship materialized over Earth, sparking the events of the game. Its enigmatic history and origins are only highlighted by its sheer mass.

The Mass Relays from the Mass Effect series open portals from one corner of space to the next. Each one is nine miles in length, making it one of the most colossal ships ever constructed in fiction. In addition, each one helps make the corners of space a little more accessible, making them, in essence, all the more colossal.

Mass Effect's Citadel is one of its most iconic spaceships. Over 27.7 miles in length and nearly 8 miles in diameter, this flying city within space truly is one of the largest spaceships ever constructed. Entire civilizations are birthed upon the Citadel, making it a center-point for all space travel.

Of the various citadels in EVE Online, the Keepstar is known as "extra-large." Each Keepstar is roughly the size of Star Wars's Death Star. These things are so colossal that even destroying one in-game results in a news-worthy event, as seen in 2016 when players managed to obliterate one.

High Charity is the Covenant's mobile planetary station. It is in essence a ship that can travel the stars while serving as a central hub for Covenant activity. It is 100 trillion metric tons in mass, over 216 miles long, and over 313 miles high. This thing is basically a homeworld for the Covenant.

Destiny's Leviathan is, in essence, a devourer of worlds. Emperor Calus uses the gigantic ship to turn worlds into a paste, devouring them for his own personal amusement. It is difficult to define the sheer mass of the Leviathan, due to just how massive the thing is. Just know that it is a planet destroyer and it will block out the whole sky if it passes near your world.

The Almighty from Destiny is an unfathomably large superweapon for the Cabal. Its exact dimensions remain uncertain. However, it is estimated to be at least 3 thousand kilometers in length -- or over 1864 miles -- at minimum. That's over half the length of the United States from end to end (which is only approximately 2800 miles in width).

The Dreadnaught is the throne world of the Hive and Oryx. The Dreadnaught, while less gloriously named than the Hive's Leviathan or Almighty, is undoubtedly bigger. At 3500 meters -- or 2174 miles -- it's the largest singular ship in Destiny. This is not a ship you want to be facing off, especially if it comes accompanied by legions of ships alongside it.

Installation 04 is more commonly referred to as "Halo." This ring-shaped starship is just one of seven Halo Rings distributed throughout the Halo Universe by the Forerunners to combat the Flood. It is also colossal. It is 6,200 miles in length, with a width of 198 miles. It's dwarfed only by one ship...

...Installation 00, the core of the Halo superweapons. This Ark is the centerpiece of the various Halo Units. It is also beyond fathoming in size. It stretches at approximately 79,244 miles in diameter. For the sake of comparison, Earth's diameter is 7,917.5 miles. It is almost the diameter of Jupiter, which is 86,881 miles in diameter. Installation 00 is larger than is humanly possible to imagine.