Misc: What English explorer discovered & named Virginia?

Questions

Which American film actor played himself in the 1955 war film biography To hell and back?

In the symbols used on clothing labels what is meant by a crossed out triangle?

What is the name of the Czech village which was destroyed on 10 june 1942 by the nazis in retaliation for the assassination of Reinhard Heydrich, deputy leader of the SS?

Name of a 1960s group and also the place in St Pauls where monks finished their paternoster on Corpus Christi day?

Name of the Aztec city on whose ruins Mexico City was founded?