Bakr Id/Eid ul-Adha
Many Muslims in India celebrate Eid al-Adha (Id-ul-Zuha or Bakr-Id), which is on the 10th to 13th days of the Islamic month of Dhul Hijja.
Elsewhere on timeanddate.com
Guru Purnima
Guru Purnima is a festival that honors spiritual Gurus by remembering their life and teachings. It is observed on the full moon day, Purnima, in the Hindu month of Ashadh, which is usually June or July.
AM and PM Explained
How does the 12-hour clock system work? Is midnight 12 am or 12 pm?
Daylight Saving Time (DST)
Why do many countries set the clocks back and forth an hour twice a year?