Yangsan Cheontae-san
Including  Yangsan Geumo-san to its north
This is a range-line of two medium mountains that are on the border between Yangsan and Miryang
Cities of South Gyeongsang Province.  They are part of the "Yeongnam Alps" sub-range famous for
tourism; and they are just north of the great Chwiseo-san (Yeongchuk-san) Tongdo-sa Monastery.

Cheontae-san is a 631-meter-high mountain, and looks south across the Nakdong River toward
Gimhae City; it is connected by its northern ridge to Geumo-san, whose summit is 730m.
  It is
famed for its many
waterfalls, including the Ungyeon Falls on its southern flank, just below the
Cheontae-ho reservoir.
Cheontae-sa 천태사 [Heavenly Platform Temple] on the southern flank of Cheontae-san is a
modern construction, but is claimed to be the original site of the Cheontae Buddhist order 天台宗,
which was established in a temple here in the 7th Century by the Korean master that studied
Tiantai Buddhism 天台宗 in Zhejiang Province of Tang China, and then imported it to Korea.

These great photos are from
Dale's Korean Temple Guide; see his post for more, and plenty info!