A yuga, in Hinduism, is generally used to indicate an age of time.
In the Rigveda, a yuga refers to generations, a period of time (whether long or short), or a yoke (joining of two things). In the Mahabharata, the words yuga and kalpa (a day of Brahma) are used interchangeably to describe the cycle of creation and destruction.
A Yuga Cycle (a.k.a. chatur yuga, maha yuga, etc.) is a cyclic age (epoch) in Hindu cosmology. Each cycle lasts for 4,320,000 years (12,000 divine years) and repeats four yugas (world ages): Krita (Satya) Yuga, Treta Yuga, Dvapara Yuga, and Kali Yuga.
As a Yuga Cycle progresses through the four yugas, each yuga's length and humanity's general moral and physical state within each yuga decrease by one-fourth. Kali Yuga, which lasts for 432,000 years, is believed to have started in 3102 BCE. Near the end of Kali Yuga, when virtues are at their worst, a cataclysm and a re-establishment of dharma occur to usher in the next cycle's Krita (Satya) Yuga, prophesied to occur by Kalki.
An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth.
Comparable terms are Epoch, age, period, saeculum, aeon (Greek aion) and yuga (Sanskrit युग).
Treta Yuga (IAST: Tretā-yuga) (Devanagari: त्रेतायुग), in Hinduism, is the second and second-best of the four yugas (world ages) in a Yuga Cycle, preceded by Krita (Satya) Yuga and followed by Dvapara Yuga. Treta Yuga lasts for 1,296,000 years (3,600 divine years).
Treta means 'a collection of three things' in Sanskrit, and is so called because during the Treta Yuga, there were three Avatars of Vishnu that were seen: the fifth, sixth and seventh incarnations as Vamana, Parashurama and Rama, respectively. The bull of Dharma symbolizes that morality stood on three legs during this period. It had all four legs in the Satya Yuga and two in the succeeding Dvapara Yuga. Currently, in the immoral age of Kali, it stands on one leg.
Satya Yuga (a.k.a. Krita Yuga, IAST: Kṛta-yuga), in Hinduism, is the first and best of the four yugas (world ages) in a Yuga Cycle, preceded by Kali Yuga of the previous cycle and followed by Treta Yuga. Satya Yuga lasts for 1,728,000 years (4,800 divine years).
Satya Yuga is known as the age of truth, when humanity is governed by gods, and every manifestation or work is close to the purest ideal and humanity will allow intrinsic goodness to rule supreme. It is sometimes referred to as the "Golden Age". Dharma (depicted in the form of a bull) symbolizes morality and stood on all four legs during this period; the legs of Dharma reduce by one in each yuga that follows. As per Bhagavata Purana, the four legs of Dharma are Tapas lit. 'austerity', Śauca lit. 'cleanliness' (or Dāna lit. 'charity'), Dayā lit. 'compassion' and Satya lit. 'truth'.
Dvapara Yuga (IAST: Dvāpara-yuga) (Devanagari: द्वापर युग), in Hinduism, is the third and third-best of the four yugas (world ages) in a Yuga Cycle, preceded by Treta Yuga and followed by Kali Yuga. Dvapara Yuga lasts for 864,000 years (2,400 divine years).
According to the Puranas, this yuga ended when Krishna returned to his eternal abode of Vaikuntha. There are only two pillars of religion during the Dvapara Yuga: compassion and truthfulness. Vishnu assumes the colour yellow and the Vedas are categorized into four parts: Rig Veda, Sama Veda, Yajur Veda and Atharva Veda.
Kali Yuga (Devanagari: कलियुग), in Hinduism, is the fourth, shortest, and worst of the four yugas (world ages) in a Yuga cycle, preceded by Dvapara Yuga and followed by the next cycle's Krita (Satya) Yuga. It is believed to be the present age, which is full of conflict and sin.
According to Puranic sources, Krishna's death marked the end of Dvapara Yuga and the start of Kali Yuga, which is dated to 17/18 February 3102 BCE. Lasting for 432,000 years (1,200 divine years), Kali Yuga began 5,126 years ago and has 426,874 years left as of 2025 CE. Kali Yuga will end in the year 428,899 CE.
The Char Dham (Hindi: चारधाम, romanized: Cārdhām transl. the four abodes), or the Chatur Dhama (Sanskrit: चतुर्धाम, romanized: Caturdhāma), is a set of four Hindu pilgrimage sites in India, consisting of Badrinath, Dwarka, Puri and Rameswaram. Badrinath, Dwarka, and Puri are shrines of Vishnu, whereas Rameswaram is a shrine of Shiva.
Defined by Adi Shankara, each dhāma represents a particular yuga, with Badrinath representing Satya Yuga, Rameswaram representing Treta Yuga, Dwarka representing Dvapara Yuga, and Puri representing Kali Yuga. Many Hindus believe that visiting these sites can help them achieve moksha.