Meydancıkkale is a fortress on a hilltop in a remote part of western Cilicia.  We know from an Aramaic inscription from the site that it was known in the Achaemenid period as the ‘fortress (byrta) of Kirshu’.  The site was already occupied in the pre-Achaemenid period, but the Achaemenid period of occupation saw the establishment of a massive fortified entrance, with – very unusually – a set of sculpted relief blocks depicting a ‘procession’ of bearded figures in Persian dress, carrying vessels in their outstretched right hands, approaching a figure in Achaemenid court dress carrying a spear. These are virtually the only examples of this distinctively royal style of ‘processional’ relief sculpture outside of the Persian heartlands.  For short discussion in English, see E. Dusinberre, Empire, Authority and Autonomy in Achaemenid Anatolia (2013), 99-101. 
For the monumentalised entrance-way (albeit on a much smaller scale), we can compare the monumental architecture of Persepolis; see also W. Held and D. Kaplan, ‘The residence of a Persian satrap in Meydancıkkale, Kilikia’, in Mesopotamia in the Ancient World, eds. R. Rollinger and E. Van Donger (2015), 175-91, comparing the architecture of Persepolis with Building A at Meydancıkkale. 
Meydancıkkale is important precisely because of how unusual it is in the archaeology of Asia Minor; this kind of explicitly ‘Persian’ architecture and relief sculpture is just not found elsewhere in the West. 
The main publication of the site is in French, but is well worth consulting for the photos: A. Davesne and F. Laroche-Traunecker, Gülnar I: Le site de Meydancıkkale (1998), e.g. pp.301-6 for the reliefs, 308-9 for the chief Aramaic inscription.