The Undercover Heir is Actually Tycoon's Secret Girlfriend - Chapter 462 - 381

Lynn traveled to a magical world similar to the European Middle Ages but possessing magical powers.

Here, magic can affect and control elementary particles.

So…a scientific theory is a magic formula!

Wizards called spellcasters who are actually scientists, under the siege of the Holy See, struggled to explore the truth of the world, until the arrival of Lin En, which set off a renaissance of an alien version…

(PS: The 2 million-word work “Hogwarts Bloodline Wizards” has already been completed, and the quality is guaranteed!)

- Description from novelbuddy

Su Bai wakes up and finds that the world has changed drastically. He realizes he has come to a world of pets. After accepting the new setting, he is determined to become a powerful Pet Tamer.

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

I’m not your slave, you bastard! She’s furious! She’s furious! I’m furious! WE’RE BREAKING UP! She’s laughing like crazy! We’ll discuss this in a hundred years She was her ex boyfriend, mother hated down and out, but he praised her as treasure, when Tsenin, you want my heart, my life, I can give you at any time