Where: In the central Mexican highlands state of Michoacán, a steep climb up from the mountain town of Angangueo.

What’s there: Mexico’s only public monarch butterfly sanctuary, which becomes carpeted, wallpapered and otherwise drenched in orange and black butterflies each winter.

Why it’s notable: El Rosario is the most accessible of Mexico’s five protected wintering grounds for millions of Monarch butterflies, which flutter from as far as Canada for a warm respite from chilly northern winters. They cling to oyamel trees in such massive numbers that tree boughs actually snap off from the weight!

How you’ll get there: From Angangueo, it’s a 30-minute drive to the gates of the reserve. Then the adventure begins—first hop in the back of an open, flat-bed truck for a bumpy ride up into the heart of the sanctuary. You’ll then hike to the spots deemed most populated by the butterflies. The hike can be tough, especially because the altitude here exceeds 9,000 feet and the terrain is steep and rocky.

Keep your eyes peeled for: The emerging sun. If it’s cloudy and then the sun starts peeking out, its warmth will begin waking the resting butterflies, which will fill the air like a flaming orange cloud.

Visit El Rosario on WWF and Nat Hab’s Kingdom of the Monarchs tour.