ATG: My genius is almost frightening! - Chapter 265 - 264: Forbidden Land of Samsara

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.

Year 20XX, the world was thrown into chaos when the Tower of Yxthar appeared...A colossal structure reaching beyond the sky, its countless floors each a gateway to a different world. These realms, seemingly connected to distant universes, spilled their dangers into Earth, unleashing monsters, invaders, and unknown horrors that threatened humanity’s survival.But from this catastrophe emerged an era of superhumans.... individuals awakened with extraordinary abilities.They became known as Stream Hunters, a title with dual meaning:“Hunter” for their combat prowess and “Streamer” because they broadcast their battles not just to Earth but across the multiverse.Through their streams, Stream Hunters gained viewers from other worlds, earning gifts and, if fortunate, the backing of a powerful Main Sponsor.Adam, an average ranking Stream Hunter, was just a background figure in their adventures... until the unimaginable happened.He woke up fifteen years before the catastrophe that would doom the world!Resigned to enjoying what little time he had left, Adam prepared for an arduous journey...But fate had another twist: he unlocked the Multiversal Livestream System...Granting him the power to copy the skills of his viewers.

Civilization is destroyed and records lost. Only Dudian survives in a cryogenic sleep. Three hundred years later, Dudian wakes up and must become Dean to survive. Who can he trust in this world overrun by monsters without and within?

- Description from Novelupdates

Zhang Ruo Chen was the sole male heir of one of the nine emperors of the Kunlun Field. Ruo Chen’s father was known to all as the “Enlightened Emperor”, however Ruo Chen didn’t just leech off his status as emperor’s son. He proved himself to be a dragon amongst men, possessing a heaven defying body, and managing to cultivate to Greater Perfection within the Yellow Horizon Realm, at just the young age of 16.

But even though he stood at the summit of the younger generation and had a boundless future, he sadly died at the treacherous hands of his own fiancee at a young age.

Reincarnated 800 years later in the body of a young boy who shares his name, he found out his former fiancee already unified Kunlun’s Field and built the First Central Empire, and was now known as Empress Chi Yao… Empress Chi Yao—Her Majesty governed the mortal world and enjoyed prestige in all directions as well as an eternal life.

Zhang Ruochen stood outside of the Imperial Ancestral Temple, looking at the statue of Empress Chi Yao, and the flames of hatred burned in his heart. “After I practice for 13 years, I shall send the empress to her doom!”

- Description from Novelupdates