It is believed that such places exist in different dimension and plane. Somewhat between physical and astral. This is referred to as Shambhala in buddhist texts, Siddhashrama and gjnana ganja in hindu scriptures and stories.
This is a fascinating subject and I recommend you to read books like Gyan-ganj and Search of Secret India.
The Gyanganj (Jnanganj) Yogashram – the ancient name of this Yogashram
was ‘Indra Bhawan’. This ancient Ashram was renovated and restored to
its pristine glory again by Swami Gyananand Paramahans, a disciple of
Maharshi Mahatapa. Under his able administration and responsible
management it started functioning properly once again under the new
Gyanganj is an extraordinary spiritual training centre. The
Brahmacharis, Brahmacharinis and Paramahansas of this centre, after
getting established in the state Aham-Brahmasmi, roam about in the
universe as, when and where they like.
The Gyanganj (Jnanganj) Yogashram with a perimeter of about 16
kilometres, is situated in the western region of Tibet, an upland in
the Himalayas to the north of India. This ancient Ashram was renovated
and restored to its pristine glory once again by Swami Gyananand
Paramhans, a disciple of Maharshi Mahatapa. Under his able
administration and responsible management it started functioning
properly once again under the new name of Gyanganj. All this
renovation took place about seven hundred years earlier, i.e., say
about 1225 A.D. Yogiraj Shri Vishuddhanand had eulogised about the
eminence of Gyanganj Yogashram in brief at times about the
supernatural experiences and powers of the Yogis of this Ashram.
About the name ‘Gyanganj’
Now ‘Gyan’ is a Sanskrit word and ‘Gan’j appears to be a Persian word.
How come that the words of these two different languages have been
joined up to form the word Gyan-ganj? In actual fact Ganj is a word,
the root of which is Sanskrit and it travelled from Bharat (India) to
Persia: Ganj : Gaji (Bhwadi ganiya Dhatu) + Yan (Pratyaya) The word
‘Ganj’ means ‘Treasury of Jewels’ so ‘Gyanganj’ literally means
‘Treasury of Knowledge of All Kinds’.
Paramhansa Vishuddhanand Ji Gandh-baba
Shri Vishuddhananda’s childhood name was Bholanath Chattopadhyaya.
Siddha Yogi Swami Nimanand Paramahansa of the secret Gyanganj
Yogashram in Tibet took Bholnath to Gyanganj ashram. Yogiraj
Vishuddhanand Paramhansadeva was the first Yogi-Saint to introduce and
propagate Surya-Vijnan, solar science, into the world for the first
time. Up till then this science was confined to the precints of the
ancient secrets of Yogashram at Gyanganj in the Himalayas in Tibet and
was known only to the ancients. Baba stayed in Gyanganj Ashram for 12
years. Surya i.e., Sun or Savita means ‘source of creation’. According
to Surya-Vijnan there are 360 rays of the sun which go to form the
whole creation of the Universe. Baba converted cotton wool, flowers
and leaves into stones, wood, etc. by the incidence of appropriate
rays of the Sun. He demonstrated practically how minute particles of
ingredients of various objects could be dispersed or assembled and
destroyed or created through the proces of Surya-Vijnan. As a result
of his adherence to the strict rules of the Brahmacharya period,
Bholanath had freed himself from the influence of ego and had also
developed the spirit of surrender to the will of the Supreme Power.