Will an iPhone 5 bought in USA work in Germany & the UK?

I'm presently working in Germany, and will be travelling to the US soon, and I need to know if an iPhone 5 (Unlocked) bought in the US will work in Germany and the UK. I currently have an iPhone 4, which works in Germany and the UK, perfectly. I understand an iPhone 5 is considerably cheaper in the US, but need to know 100 per cent, that it would work in Europe.

Will updated iPhone 4 work for all AT&T users?

I was using an AT&T iPhone 4 for a while and then got a new phone because my contract ended so I went into iTunes and reset the iPhone to get rid of all my apps and stuff but the factory reset also updated it to the newest iOS (6.1.3 or something like that) and baseband. If I give or sell my phone to another AT&T user will they be able to use it? Granted they have the micro SIM card.

Can i take my iphone to the beach?

I have all my songs for my holiday on my iphone as my old ipod isn't very good. Someone told me that if my iphone gets too hot, it won't work properly. I'm going to Turkey which is really hot in July.

Can i take it to the beach? Or should i leave it in the safe?

What is a good smartphone that isn't an IPhone?

Something that has the same functions as an IPhone. I've been through two IPhones within a year because the buttons keep getting stuck. I heard Samsung Galaxy has the same problem.

Added (1). Please add the provider if you know.

Why won't my iPhone 5 connect to Wi-Fi? - 1

It was working fine like yesterday morning and now it will not connect to my Wi-Fi. I tried resetting my modem and router. I tried resetting my phone. I restored the network settings, It doesn't even show my Wi-Fi on the list of available Wi-Fi's. I know my Internet is working because I can use my Xbox and laptop just fine. Any suggestions? Is something wrong with my phone? Help please this is really wasting my data.

Added (1). Yeah but I don't know how to make it forget the network because it doesn't even show it on the list.

How to get rid of the iOs7 beta?

I downloaded the iOs7 beta version from a youtube video, and it worked, but now my iphone 4S has a lot of bugs and keeps shutting down randomly, and most of the apps don't work. How do i get rid of the iOs7?