The term BC stands for 'Before Christ' and is used to denote years before the traditional date of the birth of Jesus Christ. This system of dating is part of the Gregorian calendar, which is widely used today. The years are counted backward from the year 1 AD, with 1 BC being the year immediately before 1 AD. In historical contexts, BC is often used to reference significant events, cultures, and civilizations that existed prior to the Common Era. For example, the construction of the Great Pyramid of Giza occurred around 2580 BC, marking a pivotal moment in ancient Egyptian history and architecture.