for all shiva bhakts who visit kashi vishwanath, please note the
following:

1. the original kashi vishwanath temple is the present gnan vapi
mosque and within this old temple namaaj is offered by muslims.
2. however, all the walls of the old temple were kept in tact upto
say one feet at the base level and the new masjid wall was
constructed over it. so a pradakshinam of this mosque would help
any shiv bhakt find traces of the original kashi vishwanath temple
where images of gods and goddesses were engraved.
3. even the old nandi (bull) of the original temple was left
undestroyed which is facing the present mosque. but thankfully this
nandi is outside the masjid complex and all shiv bhakts can touch it
and feel the positive vibrations of the original old temple and
imagine the original vishwanath shivling in front of the nandi, now
within the mosque.

the history of kashi vishwanath temple as published in Times of
India on 28.02.1995 is reproduced below:

KASHI'S OLDEST HINDU TEMPLE DESTROYED BY MUSLIM RULERS
Times of India, February 28, 1995

Lucknow: In the narrow winding lane from the Dashwashwamedh Ghat
leading towards the famed Vishwanath Mandir in Varanasi, the
atmosphere is one of extreme piety at all times of the day. The
temple is, perhaps, one of the most potent symbols of Hinduism in
the country in a city which by all accounts is one of the oldest
centers of pilgrimage for the Hindus.

The original Vishwanath temple is supposed to have been built around
490 AD during the Gupta period. Historical records suggest that it
was destroyed by Muslim rulers. The first Muslim invader to attack
Varanasi was Ahmed Nihalidin, the governor of the Indian province of
the Ghazani empire, in the 11th century. His aim was to acquire the
wealth accumulated in the temples of Varanasi. Later, Qutub-ud-din
Aibak of the slave dynasty invaded the city and more than 1000
temples are said to have been destroyed in this onslaught.

After the defeat of Ibrahim Lodi in 1526, the city passed under the
control of Afghans but was later captured by the Moghul ruler Babur.
In 1539, it was captured by Sher Shah Suri. In the tolerant regime
of Akbar, many temples and other structure were rebuilt by Hindu
kings in Varanasi.

Raja Todar mal, one of the "jewels" in Akbar's court, constructed a
new temple on the site of the destroyed Vishwanath temple in 1585.
This was again destroyed by Aurangzeb in 1669 while on his way to
conquer the Deccan. Aurangzeb got a mosque constructed in its place.
The present temple was reconstructed by Maharani Ahilya Bai Holkar
in 1777. The dome of the Vishwanath temple was gold-plated by
Maharaja Ranjit Singh in 1839.

Adjacent to the temple is the Gyanvapi Masjid, which was built by
Auragzeb on the remnants of the original temple. He had, however,
agreed to the plea of the Kashi Brahmins that a temple would be
allowed to exist adjacent to the Gyanvapi masjid as also to the
reconstruction of the Kali temple at Aurangabad, about three km
away. This temple, too, was destroyed by the invading Muslim armies.

The remnants of the original Vishwanath temple are revered by the
devout Hindus as Shrinagar Gauri, the abode of Lord Mahadev. Muslims
offer namaz in the premises of the Gyanvapi masjid but not in the
main hall.