For many hikers to Everest Base Camp in Nepal, adding an extra hike to the top of nearby mountain Kala Pattar is out of the question.
Exhaustion and altitude sickness have often already taken their toll.
But Kala Pattar, rising to 5545m, offers good views of the summit of Mount Everest and an extra challenge.
For those up to the task, take heed of these tips:
EAT BEFORE YOU GO