rouelan

not sure of this (I mean the passport). Probably true that you should always have a form of ID with you, like a driving license or an ID card. As suggested by others, an internet search should tell what the rules are in Turkey.

thinking twice after reading other posts:
There are 2 situations when police may ask you to provide a form of ID. If you commit an offense or in case of random check to verify if your presence on national territory is legal. In the 1st case, at least in France, you are not fined on the spot and thus need to provide ID to send you the fine. In the 2nd case, I guess that a passport may be needed, depending on the country you are visiting and your nationality. Still in France, random checks have become a very sensitive issue and must abide to strict rules (for example, OK near a border, or take the opportunity of even a small offense, like not punching your metro ticket, to ask for your passport). As stated by other fodorites, if you look like a bona fide tourist and not an illegal immigrant, police is likely to be lenient in many countries if you don't show a passport.

rouelan

I regularly cross France Spain border by bus and such checks are frequent. Even on local buses in the area.
And it is the same experience, that is police barely checking the passports.
the reason is simple: they are after illegal immigrants but they cannot discriminate.So, they need to act as if they were checking everybody but it is far easier to detect an immigrant by the way he looks like.

danbiggie0342

Unless you're planning to rent a car or write traveler checks or do some other bank-related work, there's no need for your original documents and it's probably a good idea to keep it safely stored in your hotel room.

Koutence

Your point about different situations where you might be asked for ID is spot on. It's interesting to see how the rules vary from place to place. Like you mentioned, in France, it seems they take random checks pretty seriously. It's definitely something to keep in mind when traveling. I think your advice about looking like a genuine tourist is valuable.

Michael

If you want to visit the entry hall of the Zurich police station which used to be an orphanage, you must surrender your passport, not a copy, at the desk.

Koutence

Being respectful and cooperative can go a long way if you do find yourself in a situation where you need to show ID. Oh, and speaking of assistance with travel documents, have you heard about keta korea? They're supposed to be really helpful in that regard. Might be worth checking out if you ever find yourself in need of some extra support abroad.

Ez73

There are better ways of getting valid and accurate information than by asking a travel form. Check government travel advisory sites.

This is a quote from an official UK gov website for Turkey specifically:

Personal ID

"It is illegal not to carry some form of photographic ID in Turkey. Always carry your passport or residence permit. In some busy areas, especially Istanbul, the authorities may stop people for ID checks. There are also several police checkpoints on main roads across Turkey. Cooperate with officials conducting checks."