Incredible footage has emerged from North Korea showing troops breaking through blocks, tiles and bricks with their bare hands with Kim Jong Un watching on.
A video broadcast by state media also shows bare-chested troops displaying their pain tolerance by laying on broken glass and beds of nails, alongside others running and chopping through a variety of building materials.
The Defence Development Exhibition, 'Self-Defence 2021', saw Mr Kim, the country's leader, watch on with delight from the stands.
In what South Korean media reported to be the first such exhibition held by the North, footage appeared to show one individual break out of restrictive chains using brute force and others break concrete blocks over troops' stomachs with sledgehammers.
The display was part of events to mark the 76th anniversary of the ruling Workers' Party.
The 'self-defence' show also saw Mr Kim review a rare exhibition of weapons and vow to build an "invincible" military, citing the US' lack of 'action' to prove it has no hostile intent towards North Korea.