Saint Kabir once said -
"Guru and God both appear before me. To whom should I prostrate? I bow before Guru who introduced God to me."
The word guru takes its origin from gu, darkness and ru, light. Thus guru in the spiritual sense shows others knowledge (light) and destroys ignorance (darkness). Some of the spiritual leaders of the 19th and 2oth centuries are Ramakrishna Paramahamsa, Ramana Maharshi, Paramahamsa Yogananda, Anandamayi Ma, Prahlad Chandra Brahmachari and Gopi Krishna. Interestingly, there are some western spiritual leaders who have embraced the Hindu spirituality and have earned the status of a guru. They include Franklin Merrell-Wolff, Paul Twitchell etc to name a few. You can read their biographies at the following link.