In the Buddhist calendar there are special days set aside to commemorate the four great deeds of Shakyamuni Buddha. On these days, the effects of positive or negative actions are multiplied by ten million times, so they are great dayS for accumulating merit.

Usually, many hundreds of people do Kora (circumambulations) at both the Boudhanath  and the Swayambhunath Stupa in Kathmandu, make pilgrimages to holy places, offering lights, doing long prostrations on the circumambulation circuit, offering whitewash and prayer flags at the stupa, and many other merit gathering activities.

At the monasteries, special pujas are held with extensive prayers and offerings, and in some of them, a purification retreat, a two day fasting retreat (Nyung ne) is practiced.

Read here Lama Zopa Rinpoche's advice on the benefit of circumambulation stupas.

Read more on practices you can do on special days

Chotrul Duchen - Day of Miracles (15th day of the 1st Tibetan Month)

On this day, the leaders of India's six main philosophical schools challenged the Buddha to a contest of miraculous powers. The Buddha displayed a different miracle every day for 15 days and utterly defeated his challengers.

The Annual Great Prayer festival (Monlam Chenmo), established by Lama Tsong Khapa in Tibet in the 14th century, is held in conjunction with this special day at Kopan.

Saka Dawa Duechen (15th day of the 4th Tibetan Month)

This day marks the day of Buddha's Enlightenment in Bodhgaya at the age of 35 under the Bodhi tree. The place itself is now one of the most important pilgrimage places for Buddhist from all over the world. The day also marks the anniversary of the Buddhas Paranirvana in Kushinagar.

Many people cirumambulate stupas, and in some monasteries and centers Nyung ne, a two day purification practice,  is held. The Kopan nunnery holds every year 8 sets of this two day practice. Around the Boudhanath Stupa  the famous overnight kora is organized on this day. Thousands of people, old and young, come to circumambulate the great Boudhanath Stupa. Everywhere light offerings are made by devotees.

Choekar Duchen – the First Turning of the Wheel of Dharma (4th day of the 6th Tibetan Month

For seven weeks after his enlightenment, Buddha did not teach. Finally he turned the wheel of Dharma for the first time at Sarnath, teaching the Four Nobel Truths. You can visit the place in Sarnath where Buddha gave his first teachings. It is located in a big park with a stupa, and the ruins of a monastery that existed there.

Lha Bab Duchen – Buddha's descent from Tushita (22nd day of the 9th Tibetan month)

This day marks Buddha Shakyamuni's descent from heaven. Buddha's mother was reborn in Indra's heaven. To repay her kindness and to liberate her, and also to benefit the gods, Buddha spent three months teaching in the realm of the gods.