[Isobel]

Chase Sapphire Preferred or Chase Sapphire Reserve is a good bet.

[Chet]

The broad answer will be one without a Foreign Transaction Fee.

Which cards do you have? Chase Sapphire Reserve, Chase Sapphire Preferred, Chase Ink, Citi Premier, Amex Gold, Capital One Venture or Capital One Venture X are all good options and will earn different level of points.

A Visa or Mastercard will be accepted pretty much everywhere and in some places Amex can be problematic but that is less of an issue in the UK and major cities in Europe.

The Sapphires are popular for many reasons but one stands out are the travel protections which can save you some headaches while traveling. Other cards do have travel protections too but the Sapphire protections tend to be broad.

[Percy]

I had used Amex in general more so than any of my Chase cards while out of the country.

This is whenever a merchant accepts Amex since not all of them do.

I found the exchange rate from Amex is better than Chase.

I am sure this is anecdotal but that has been my experience.