A white, cotton or linen shirt truly evokes a sense of travel and holiday to me - from beachside lounging to being on your feet in the city all day to trekking through jungle and forest. It translates to every occasion and holiday 'type' - casual, chic, adventurous, summer, autumn, active, relaxed. Even better when you can roll up the sleeves and button them secure, in "Oh, this outfit? No, it required no effort at all" nonchalance.
My ultimate reach-for item when abroad.
This gorgeous location was Rumelihisarı, a fortress from the Ottoman era. It's so worth visiting. There are hardly any other tourists, you get breathtaking views of Istanbul and you have the run of the place (almost - there are one or two restricted areas, but no guards or security). Definitely avoid going on a rainy day - the many steep, uneven steps will be slippery and there is nothing to hold onto. Entry is very cheap and it's worth going even just to sit on a bench and take it all in for an hour or so.