The vacation period is a minimum standard in the EU.

Beyond the daily and weekly rest periods, your staff has the right to at least 4 weeks of paid holidays per year. You cannot replace these holidays with a payment unless the employment contract has ended before the staff member has used up all their annual leave.

In the UK minimum holiday entitlement is 28 days. I am always appalled at how badly the US allows it workers to be treated. I really wish the US would start thinking more about working to live and not living to work.