Post cards, letters and care packages are some of the best ways to keep in touch with loved ones back home while traveling. Just a short walk from Centraal Station and very close to Dam Square, you'll find the post office, filled with everything you may need. You can go right up to the counter to buy stamps if you already have your correspondence ready. Or you can browse the assortment of cards and postcards available. You can also purchase a box if you need to mail tasty treats or Dutch souvenirs. The post office has every size box, from small to large. If you have a day or two in Amsterdam, you can also buy an OV chip card, which is valid for the public transportation.