Washington D.C. - major attractions, transportation?

what are the major attractions in Washington D.C. and is there a good public transportation? maybe some ideas about day tour.thank you

The Smithsonian Complex-Museums and Art /Crystal City Shopping Mall and The White House might still be there?....Subway and it's walkably small

One can spend three days in DC, and still not see it all. The Smithsonian Institute is a must. You can spend a whole day in there and not see it all. Right across the street or mall is the Museum of NATURAL HISTORY.. Awesome! Right up the street is the Botanical Gardens.

There is too much to mention. But above all dont stray off of the beaten path.. Stay out of the subways. DC is a very dangerous city..

youtube.com/watch?v=LUfOl5NXNmY&feature=related

If you stay in the Mall. Everything is within walking distance.. The WASHINGTON MONUMENT
White House, Capitol Building,, This area is well patroled and you face no danger.

Good Luck

+1 for what nunczka says. You can also scoot by the Marina in Baltimore, right next door, but avoid downtown especially after business hours.

Walking around the area, if you don't know it, may be chancy. Rent a car.

I agree. The DC has many many museums, memorials and sites worth to see. I recommend this place during Spring when cherry trees are blooming.