Crew members inside the massive cargo hold of an LNG (Liquid Natural Gas) tanker.

 

The tank shape is a tradeoff between maximizing the usable space within the hull and containing the pressurized LNG. The pressure is fairly low, around 20 kPa or 3 psi, but applied over such a huge area that produces a lot of force. There are other types of LNG carriers with spherical tanks which are simpler but less space-efficient.

The texture is a stainless steel liner designed to handle expanding and contracting in two dimensions through large, rapid temperature changes, as the LNG is around -160 C / -260 F.

For anyone else interested, here's a really really simplified explanation of the different tank types.