For any travelers going to Greece, Tauck's info correctly indicates you have to fill out an electronic travel form for the Greek government prior to arrival. Don't wait until the last minute to do this. It takes (multiple attempts for me) to get the form submitted. There is not any "help" on the site. They require your cellphone number. Enter a "+" followed by the number "1" and then your cell phone area code and number. Do not include the usual double "00" before the country code "1" . The form won't recognize the number and will lock up. Took me a while to figure this out.