Martial Universe (Wu Dong Qian Kun) - Chapter 1231: Darkness City

Julietta, born as an illegitimate child of a nobility, is raised in an opera theatre to hide away from the eyes of the noble’s main wife.

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.

Haewon, a violinist, is a nonchalant person who neither blocks the ones who come into his life nor holds onto those who leave. One day, his only friend, Taeshin, commits su*cide, and after failing to speak to Taeshin, who called him several times shortly before his death, Haewon is haunted by his death, even though he doesn’t have much of an attachment to human relationships. Then, he inevitably runs into Woojin, the man Taeshin had a crush on, and Haewon indifferently crumples up the business card Woojin hands him.One day, Haewon, forced into an unwanted relationship, becomes entangled in an assault case, but thanks to the business card given to him, he receives help from Woojin, who’s a prosecutor. Haewon feels uncomfortably guilty and tries to keep him at arm’s length, but Woojin is comfortable enough to take a few extra steps.

Reborn into another life as a village boy,Lu Changsheng unexpectedly discovers that he awakens a very low-profile longevity system.The longer he lived, the better his cultivation talent would become!