Vethathiri Maharishi, also known as Yogiraj Sri Vethathiri Maharishi or Siva Yogaswami, was a prominent spiritual teacher, philosopher, and yoga master from Tamil Nadu, India. He was born as Vethathiri on August 14, 1911, in Guduvancheri, Tamil Nadu, and passed away on March 28, 2006.

Vethathiri Maharishi was a proponent of simplified Kundalini Yoga, a form of yoga that he developed based on his own experiences and insights. He believed in making spiritual practices accessible to all individuals, irrespective of their religious or cultural background. His teachings emphasized the harmony between science and spirituality and focused on promoting physical, mental, and spiritual well-being.

Throughout his life, Vethathiri Maharishi authored numerous books on various topics, including yoga, self-realization, holistic health, and philosophy. He founded the World Community Service Center (WCSC), a non-profit organization, to disseminate his teachings and promote global peace and harmony.

Vethathiri Maharishi's teachings continue to have a significant impact on many people's lives, and his organizations carry on his mission to spread his knowledge and practices.

Vallalar, also known as Ramalinga Swamigal or Saint Vallalar, was a highly revered Tamil poet, philosopher, and spiritual leader in the 19th century. He was born on October 5, 1823, in Marudur, Tamil Nadu, India, and he disappeared from the physical world on January 30, 1874, in Mettukuppam, Tamil Nadu.

Vallalar's teachings are deeply rooted in the principles of love, compassion, and service to humanity. He believed in the universality of religion and sought to promote the unity of all people, transcending the barriers of caste, creed, and religion. Vallalar's main message was to realize the oneness of all existence and the inherent divinity within each individual.

One of his most significant contributions was the establishment of the "Samarasa Suddha Sanmarga Sathiya Sangam," a spiritual organization that aimed to spread his teachings and provide assistance to the needy. Vallalar's teachings emphasized ethical living, vegetarianism, and compassion towards all living beings.

Vallalar is also known for his exceptional poetic talents. He composed numerous songs and poems expressing his spiritual insights and devotion to the divine. His works continue to inspire and guide millions of people in their spiritual journey.

Vallalar's followers, known as "arutpaadals," continue to honor and practice his teachings, and his legacy has left a lasting impact on Tamil culture and spirituality. His contributions to Tamil literature and philosophy, along with his profound spiritual teachings, have made him a revered figure in South India.

Swami Vivekananda was a renowned Indian Hindu monk, philosopher, and spiritual leader who played a crucial role in introducing Indian philosophies of Vedanta and Yoga to the Western world. He was born as Narendranath Datta on January 12, 1863, in Kolkata (formerly Calcutta), India, and passed away on July 4, 1902.

Swami Vivekananda was a disciple of the great saint and philosopher Sri Ramakrishna Paramahamsa. After the passing of his guru, Vivekananda traveled extensively in India and later embarked on a significant journey to the United States in 1893 to represent Hinduism at the Parliament of the World's Religions held in Chicago. His eloquent speech at the parliament, addressing the audience as "Sisters and Brothers of America," received widespread acclaim and introduced Hinduism and Indian spirituality to the Western world.

After his successful visit to the United States and Europe, Swami Vivekananda returned to India and founded the Ramakrishna Math and Ramakrishna Mission in 1897. These organizations aimed to promote the teachings of his guru and serve humanity through various educational, social, and humanitarian activities.

Swami Vivekananda's philosophy emphasized the idea of the divinity within each individual and the oneness of all religions. He believed in the unity of all beings and stressed the importance of selfless service, compassion, and spiritual realization.

His teachings and writings, including books such as "Raja Yoga," "Karma Yoga," and "Jnana Yoga," continue to inspire people around the world. Swami Vivekananda's impact on modern Hinduism and the promotion of Indian spiritual heritage in the West remains significant, and he is considered one of India's greatest spiritual leaders and cultural ambassadors. His birthday, January 12, is celebrated as National Youth Day in India in honor of his contributions to the youth and society.