KUALA LUMPUR, Jan 5 — Weeks of research and surveillance, over 20 hours of hiding in a small concrete box and soreness summed up the Russian daredevil Angela Nikolau's quest to climb Merdeka 118.

The seasoned rooftopper, who went viral for climbing to the top of Merdeka 118 building with her partner, recounted the "hardest climb” of her life in a Twitter thread.

This comes after the police opened an investigation over the authenticity of the visuals of the couple atop the building went viral.

Nikolau and her partner Ivan Beerkus are known for daredevil stunts, having climbed several skyscrapers all over the world.

She said in the Twitter thread of multiple posts that she fell in love with Merdeka 118 tower the moment she saw it, and she decided to "discover” it.

"I rented an apartment with a good view of the tower so I could conduct surveillance of the building.

"I spent several weeks finding out important details I needed to know before going there.”

To start the mission, the 29-year-old said she wore a hijab, glasses and builder’s uniform to be unnoticeable.

"I ran the first 32 floors and got overheated.

"I had to lie down on the concrete floor naked to cool down a little bit. I drank all the water I had.”

The trouble came after Nikolau was detected while she was relaxing.

"I sheltered in a small concrete box where I could not even stretch my legs.

"I didn’t know I’d have to spend more than 20 hours there.”

After nearly 25 hours, she got going and ran to the spire while the workers were on their break.

She then managed to complete her mission by claiming the 53-floor high spire.

"The climb was the hardest one of my life and I'm not sure I'd be able to do it again.

"But the beauty I saw and could capture and share with you is incredible.”

Nikolau said she respects the laws of every country despite trespassing sometimes.

She, however, said she takes special care not to cause any damage to anything.

"My goal is to create memorable art by capturing the moments of the world’s tallest buildings.”

News of Nikolau and Beerkus scaling the 679-meter building first broke on December 27, after a photo of the couple atop the tower was posted on SkyscraperCity.com.

The couple confirmed their stunt two days later on Instagram by posting videos and drone footage of them on the peak of the skyscraper’s spire.

Nikolau and Beerkus are currently under police investigation for trespassing on private property.

There is currently no indication of the whereabouts of the couple.

Nikolau also said she would be putting up an NFT dedicated to the effort tomorrow for "someone else to own this achievement too”.