I have just got back from London. (Present Perfect)
The weather was terrible there, but I had a great vacation. I went sightseeing a lot. (Past Tense Simple)
I saw the Houses of Parliament, the Buckingham Palace, the Tower of London and other places. Most of all I liked Madame Tussaud's Museum. (Past tense Simple)
That is all for now . (Present Tense Simple)
Love, John.