What is the ruling on traveling to non-Muslim countries (like Turkey and Europe) for tourism, and does the hadith: "Journeys are not to be undertaken except to three mosques: the Sacred Mosque [in Makkah], this mosque of mine [in Madinah], and Al-Aqsa Mosque [in Jerusalem]," apply to it?

The meaning of the Hadith: "Journeys are not to be undertaken except to three mosques..." is a prohibition against traveling for the purpose of worship and prayer except to these three mosques, unlike other types of travel such as for trade, medical treatment, or tourism. The default ruling is that travel for tourism, leisure, and recreation is permissible, and it is allowed as long as it is not a journey of disobedience. Scholars have differed regarding giving zakat to a traveler for leisure. As for travel to lands of disbelievers or Muslim lands where open transgressions are apparent, some scholars have explicitly stated its absolute reprehensibility, while others have permitted it with conditions. It becomes forbidden if one does not feel safe from temptation. Turkey is a Muslim country.