Day 3 marks a big ascent to an elevation that can make or break the climb. Climbing to over 4000m is a good test elevation for how you will do with the altitude. Climb directly toward Mawenzi Peak to the tarn located below is towering cliffs at 14,180 feet. At this elevation, if someone is going to develop acute mountain sickness, this is often when the symptoms may begin. Many climbers opt to take acetozolamide to reduce their risk of getting AMS and other high altitude related complications. Consult with your physician before you leave and bring the medication with you as it is useful in the treatment of AMS. As with any altitude related illness, descent is mandatory if symptoms worsen, especially if headache or shortness of breath become progressively severe.