10 Underrated War Horror Movies

10. Sauna

It's easy to mistake Sauna as a spoof, considering it revolves around an evil bathhouse. Goofy premise aside, there's nothing funny about this 16th-century war drama.

Shortly after the Russo-Swedish war ends, brothers Knut and Eerik are tasked with marking out the borders of their new kingdom. After killing a peasant and leaving his daughter to die, the siblings abandon their mission and head to a sauna in the marsh, hoping to wash away their sins. Upon entering the remote spa, Knut and Eerik find themselves tormented by a hostile phantom.

What makes Sauna unnerving is how it's hard to tell what's real and what's isn't. Not only is it told in a non-linear fashion, it's obvious the brothers had major issues before setting foot in the steamy chamber. Eerik suffers from failing sight while Knut has been hardened by his time on the front line. When the bathhouse intensifies these insecurities, it's not clear at first whether they're wrestling with their subconscious or if they're legitimately being haunted.

It may be a psychological drama as much as it is an outright horror, but Sauna will leave anyone rattled due to how effectively it explores guilt, sin, and redemption.