If you love hiking and outdoor activities, then you should definitely check out Reykjadalur valley. The trail takes you through stunning landscapes with bubbling mud pots and steam vents before leading to a river where you can soak in warm pools surrounded by nature. It's a unique combination of hiking and hot springs that offers a relaxing and scenic experience.
The trail is covered in snow during winter months, so good hiking boots or mini-crampons are a must. Also consider that you'll be changing on snow, so flip flops or a matt is a great idea.