sentences:  The major tributary of the Penzhina is the Aklan, Oklan or Khayakha River which flows southeast and joins the Penzhina about 50 miles from its mouth.In 1669 the Russians built the ostrog of Aklansk, which was used to subdue the local Koryaks and was an important base on the route south from Anadyrsk to the Kamchatka peninsula before the sea route from Okhotsk opened up.It was attacked by the Koryaks several times and later abandoned.