Famously Mundane, Fictionally Magical

A sub-trope of Public Domain Artifact, this is the one where real life objects of notable historical value (that indisputably exist or existed in real life) are given a magical makeover in a work of fiction. Think of it as the inanimate version of Beethoven Was an Alien Spy or a Historical Object Upgrade. Can be related to Clap Your Hands If You Believe or Weaponized Landmark.

Examples of Famously Mundane, Fictionally Magical include:

Comic Books

Stormwatch PHD had a villain seeking to mystically weaponize the Nuclear Doomsday Clock.
Drawing on fringe occult theories, From Hell suggests that Christopher Wren's churches are examples of occult architecture.
The Golden Age DC Comics heroine Liberty Belle somehow derived her powers from the "mystic vibrations" of the Liberty Bell.
In Vertigo Comics series like Hellblazer, The Sandman, Shade the Changing Man, and Doom Patrol, this is an Invoked Trope: well-known artifacts and items often possess mystical properties because so many people know of them, investing them with spiritual significance.
One Gentleman Ghost story somewhere which involves him doing a summoning ritual with the rope that was used to hang a famous criminal in Victorian England.
The Umbrella Academy shows the Eiffel Tower being a spacecraft/weapon piloted by Zombie Robot Gustav Eiffel.
- It was a common folk belief until the 19th century that hangman's ropes had special, mystical power after being used. A century or two earlier even learned doctors considered that a possibility.
One Doctor Strange miniseries had the good Doctor being grievously wounded by the pistol that Hitler had used to commit suicide, the idea being that there was likely enough negative mojo in there to pierce even the Sorcerer Supreme's defenses (and there was).

In Hudson Hawk many of Leonardo da Vinci's most famous artworks contain the components of an alchemical device for making lead into gold.
The Mummy: Tomb of the Dragon Emperor featured the Terracotta army of Shihuangdi coming to life.
In the 2015 film Tomorrrowland, the Eiffel Tower is actually the launch gantry for a secret rocket/interdimensional transport capsule.

The Hope Diamond
Tutankhamen's tomb and its contents
The Porsche, nicknamed "Little Bastard," in which James Dean suffered a fatal car accident, as well as many other supposed "death cars."
I'm sure the Voynich Manuscript has been used somewhere.
- In Broken Sword 3 it contains the secret to extracting life energy from Ley Lines.
Artifacts and concentration camp sites from The Holocaust have been described in stories as having dark power from the suffering that was associated with them.

Elizabeth Bear's Promethean Age books use the Golden Spike as the lynchpin of a mystical anti-faerie enchantment. Railroads and iron, doncha know.
- They also feature one of the lions in front of the New York City Public Library as a Genius Loci.
The Underworld Cycle has Wyatt Earp's handgun, which is capable of killing unquiet dead (ghosts and spookies that walk around in The Between.)
One short story in The Dresden Files universe features the musket ball that killed Nelson at Trafalgar. It is reused as a sorcerer-slaying weapon.
- The Shroud of Turin also shows up, toying with this trope. Though of course many people in the real world believe it's by no means mundane, Harry mostly agrees with the theory that it was a medieval forgery. The thing is, in the Dresdenverse, tens of millions of people literally can't be wrong about something being mystically potent.
In The Kane Chronicles, the Rosetta Stone is this.

Geist: The Sin Eaters has Memorabilia, extremely powerful items given their power by being associated with the deaths of the famous. Such examples include the ring Joe DiMaggio slipped on Marilyn Monroe at her funeral, JFK's death car, the pistol that killed Lee Harvey Oswald, and the National Enquirer's photo of Elvis in repose.
The New World of Darkness also has the Reliquary book, which provides rules for building magic items from scratch, as well as a number of sample items. Among them are Shakespeare's lost play, the Dendera lights, and the Baghdad batteries.
Deadlands is chock full of these: the list includes the muskets of the Conquistadors, Wild Bill Hickok's guns, Hoyle's Rules of Games, etc. - all magical items.
GURPS Warehouse 23 has a Real Life artifact, the Mitchell-Hedges crystal skull. It allows its owner to cast a powerful Divination spell, and has powerful telepathic abilities in its own right.

The World Ends With You turns the Shibuya River into an extradimensional nexus.
The STALKER series has the Chernobyl Nuclear Power Plant Exclusion Zone (AKA "The Zone") as (even more of) a Death World packed with mutants, physics defying fields that appear and reappear in new locations over time and spawning Super Power At a Price giving items. It is the result of mad scientists operating within the conveniently abandoned area to escape prying eyes, not the disaster itself.

SCP Foundation:
- SCP-157-ARC, a bullet that, thanks to its mystical properties, apparently shifts shape to transform into the projectile used in virtually every major modern assassination.
- Another SCP entry concerns the so-called Demon core, which is apparently sentient or close to it.
- SCP-099 is the original version of René Magritte's "The Portrait", which has the memetic effect of inducing paranoid delusions.
The Academy of Superheroes universe has the Worldmaze, a Portal Network created using the globally-scattered pieces of the Berlin Wall as foci.
- The Great Pyramid at Giza was revealed to be a power accumulator that after five millennia had enough juice to make one a god.
- Magellan's oceanbound route around the world is used by Q'Nos to summon Jorumngandr. Peregryn counters the summoning by tracing the path of the Lucky Lady II, the first plane to circumnavigate the globe.

The Real Ghostbusters episode "The Ghostbusters in Paris" reveals that the Eiffel Tower is actually a primitive ghost trap.