Istanbul
Can you mix base-game and expansion Place tiles in whatever layout you like?
Not by the rules as written. The base game uses a 4x4 grid of its 16 tiles; one expansion adds 4 or 6 tiles for a 5x4 grid; using both expansions (the Great Bazaar) makes a 5x5 grid with all 25 places and the Fountain in the centre. There is no printed fixed 5x5 layout, so the random Great Bazaar layout is the one to use, with the Tea House and Black Market kept apart.