I have one question please help out it if you have faced it.

I have heard that they need a valid visa on your passport to travel through certain countries. When i came to US i had f1 and it was for 5 years so if you look at the dates its still not expired. but now i am in h1 so technically that visa on my passport is of no use. So will i be able to travel though london for example with the vias on my passport.