Spent two weeks hiking into the Himalayas with 14 other trekkers and two Nepali guides. We reached EBC (5364m) on day 9 and Kala Patthar (5545m) on day 10. It took 3.5 days to walk back down. It was the most epic hike I've ever done. The entire journey was just as beautiful and magnificent as the destination.
Some of us experienced symptoms of altitude sickness. At around 4000m, I started having pounding headache and was often out of breath doing menial tasks such as rolling over in my sleeping bag. The last climb to Kala Patthar in the -12°C temperature with only 50% oxygen in the thin air was one of the hardest things I've ever done. The cold didn't bother the Norwegians, but being from Vietnam and living in Hawaii, I had a hard time with it.
Overall, it was a great adventure and an experience of a life time.