That's a very interesting question! Just the other day my husband and I were visiting one of our favorite places, The Residence (I honestly can't remember whose, we just call it The Residence) in a city near us in Wurzburg, Germany. It was commissioned in 1720 and completed in 1744...it's a BEAUTIFUL place filled with wonderful paintings, statues, etc...and I told my husband if we could time travel, I'd want to go back maybe in the early 1740s and see it being finished and then watch its owner move in and throw a party or something. I wouldn't want to actually BE there, in fear I'd mess it up, but maybe like a fly on the wall? That would be awesome.
I'm not sure if I'd want to see the future...there's so many cool things to be seen, but I'm worried there could be not-so-great things...and I'm not a big fan of spoilers.

I'd have to think about it...but still, great question!