* Number of days in each month: Both calendars have the same number of days in each month, except for February (28 days in a common year and 29 in a leap year).
* Days of the week: Both calendars use the same days of the week, starting with Sunday and ending with Saturday.
* Leap years: Both calendars have a leap year every four years, except for years divisible by 100 but not by 400.
However, there are a few minor differences:
* Weekends: While both use the same days of the week, some countries, including Spain, consider Saturday and Sunday as the weekend, while other English-speaking countries may consider Friday and Saturday as the weekend.
* Holidays: Both calendars have different national holidays depending on each country's traditions and culture.
* Date format: While both use the same numerical values, they may differ in the format of writing the date (e.g., Month/Day/Year vs. Day/Month/Year).
In summary, the English and Spanish calendars are nearly identical, sharing the same core structure and organization of the Gregorian calendar system. The minor differences mostly revolve around cultural and national variations.