The Detective is Already Dead - Chapter 156 - 4.6

If you had a chance to live again, what would you do? Earn money, hold onto a thick leg, just find someone to live a happy life with? Ha ha… Stepping on the beat of the times, riding the wind and breaking the waves, strategizing, using your knowledge to change yourself, and everything around you, come back! The reality flows to the plot, the golden fingers are thick, slow, and cool.

- Description from Novelupdates

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.

Gods and demons fought, the worlds collapsed, only eternal immortal realm, lasting in the world.

After eternity, a god of war named Zhao Yun condensed the heavens and the earth, recast the cosmos, from the blue to the earth, marked the eternal immortal realm, in the name of the god, the king is over the world.

Since then, what he said is a myth.

- Description from MTL

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates