This week: A beautiful labyrinth and misty fog. Then, in Transylvania, see a tender moment between a man and his horse, and guess the age of this sea animal.

PHOTOGRAPH BY FRANCOIS-XAVIER DE RUYDTS

Near the peak of Mount Rainier, tucked within the majestic volcano’s east crater, lies a network of dark and vast ice caves. The caves can be awe-inspiring, and this image by photographer Francois-Xavier De Ruydts captures their magic. The swirling mists of fog are created when the crater floor is warmer than the air.

More stories:
— These birds are keeping a record of humanity—one wrapper at a time

PHOTOGRAPHS BY JOEL SARTORE 

Scientists are racing to save sea stars from extinction through breeding, and they're learning all about the different species. Above is a sunflower sea star. What is its average life span?  

A. 10-35 years
B. 25-65 years
B. 35-85 years
D. None of the above

PHOTOGRAPH BY GEMMA MIRALDA

Transylvania is one of the best known regions on Earth, but it might also be the least understood. In this photo, photographer Gemma Miralda captures a moment between Golicza József and his horses. Professionally, József tends to herds of cows. But after work, he practices dressage, relying on affectionate bonds to train his horses.

BEFORE YOU GO: See what is possibly the oldest tree on Earth. And learn why it may not survive climate change. 

Thanks for reading today’s newsletter, which was edited and curated by Jennifer Baik and Melati Maupin. It was produced by Amanda Petty. Did someone forward this to you? Sign up here to catch next week’s Photo of the Week newsletter.