Around six months of the year are spent closed at the high-altitude shrines, which open in April or May during the summer and close in October or November when winter arrives. It is thought that the Char Dham Yatra should be completed in a clockwise fashion. Thus, the pilgrimage begins in Yamunotri, moves on to Gangotri, Kedarnath, and eventually Badrinath. Both air travel and road travel are options (helicopter services are available). Some followers also go on pilgrimages to the shrines of Kedarnath and Badrinath, known as the Do Dham Yatra.