how come I have basic game and all DLC and I can enter this ?

I cannot remember to be honest. This has sat in my inventory for a few years and the steam page no longer works for it. I'm pretty sure if adds everything in gold edition that isn't in the base game.

Quick google search leads to this:

Civilization V: Cradle of Civilization - Mediterranean, Civilization V: Cradle of Civilization - Asia, Civilization V: Cradle of Civilization - Americas, Civilization V: Cradle of Civilization - Mesopotamia, Civilization V: Explorer’s Map Pack, Double Civilization and Scenario Pack: Spain and Inca , Sid Meier’s Civilization® V: Babylon (Nebuchadnezzar II), Sid Meier's Civilization V - Gods and Kings, Civilization and Scenario Pack: Polynesia, Civilization and Scenario Pack: Denmark - The Vikings, Civilization V - Civilization and Scenario Pack: Korea, Civilization V - Wonders of the Ancient World Scenario Pack

Which does look familiar.