Holi (Hindi: होली) is a religious spring festival celebrated by Hindus, also known as the Festival of Colours. It is primarily observed in India, Bangladesh, Pakistand and Nepal and in countries with large populations from India or of Indian descent who follow Hinduism.
Yatra (Sanskrit: यात्रा, "journey", "procession"), in Hinduism and other Indian religions, means pilgrimage to holy places and is generally undertaken in groups. One who goes on a yatra is known as a yatri. It is desirable, but not obligatory, for a Hindu to go on a yatra. One can go on a yatra for a variety of reasons, including festivals, to perform rituals for one's ancestors, or to obtain good karma. To traditional Hindus, the journey itself is as important as the destination, and the hardships of travel serve as an act of devotion in themselves. Visiting a sacred place is believed by the pilgrim to purify the self and bring one closer to the divine. (Thanks to Wikipedia for these definitions.)
Shree Shakti Mandir is one of the least ostentatious places of worship I've had the pleasure of visiting in the city. It's a single storey concrete building in a residential area and would be easy to miss or mistake for something else. First sight of the premises reminds me of a scout hall or something similar. It also brings to mind the Italian Chapel on Lamb Holm in the Orkney Islands, which I've visited twice (in 1984 and 2008). This building was previously used as a Roman Catholic church (Our Lady of Good Counsel). On the other side of the building from where we enter (on Moira Street), Christian symbols have been left visible, quite deliberately as a way of emphasising the religious harmony of previous and present use.