I did that flight a couple years ago. Yes, it's about 15 hours. No, it's not as horrific as you might imagine. I used South African Airlines, and they were absolutely wonderful. They kept me fed and comfortable (in coach). Make sure you take an iPad with lots of movies. Eat and drink whenever they offer it, especially water. They even had a little snack bar set up in the galley. Wear very comfortable, loose-fitting clothes. Get up and exercise and drink water frequently to prevent blood clots. They had on-board entertainment screens in every seatback, which unfortunately didn't work on the way over, but did on the way back. When you get there, try to stay up until the local bedtime. Get a good travel pillow. Hope that helps. I think the main thing is to keep a healthy frame of mind. That's a long time to be stuck in one place. Try not to go stir crazy!