Answer:
When the value of a currency A is rising against another currency B, it means that currency A is appreciating against currency B. This happens when there is a higher demand for currency A in country B, than the demand for currency B in country A.
When Europeans go on vacations in the US, and the Euro is appreciating against the US dollar, it means that 1 € will purchase more US dollars (at least a bigger fraction). So things here will be cheaper for them.