Which are the top 5 must-see archaeological sites in North Wales?

Snowdonia Mountains and Coast have advanced the case for:

Bryn Cader Faner

1. Segontium - the Roman fort on the outskirts of Caernarfon.

2. Tre'r Ceiri - the Iron Age Hill Fort on Yr Eifl.

3. Bryn Cader Faner - the Bronze Age cairn near Harlech.

4. Dinas Emrys - a place from Welsh Mythology near Beddgelert.

5. Tomen y Mur - a Roman fort refortified in Norman times near Trawsfynydd.

see http://visitsnowdonia.wordpress.com/2012/09/24/ancient-snowdonia-five-must-visit-sites/

What do you think? Are there any of your favourite places that you would like to add?