When visiting any museum and some other tourist attractions be aware that on certain days entry is free for European Citizens, providing you have an ID card or Passport.  This can be a little confusing when entering a museum to be asked for your passport if you dont understand the reason.  The Naval Museum is attached to the Ministry of Defence so they ask for identification as a security precaution.

There is also a dislike of 'daysacks', or small rucksacks, in many museaums and they will ask for them to be deposited in the cloakroom or carried in the hand rather than over the shoulder.  As other people are still allowed to enter with large shoulder bags it is felt that this is more to do with preventing accidents, e.g. exhibits getting knocked over, than to do with security.

Before taking photographs in the museums check to ensure that it is allowed, and if allowed that flash photography is allowed.

For sites, the museums aren't to be missed.  The Spanish controlled the known world for centuries, and amassed an amazing art collection. 

Museo del Prado is a ¨must-see¨... many of the greatest masterpieces in the world are housed there. Greco, Velazquez, Goya, Bosch, and the list goes on. Make sure to get the audioguides for 4euro. 

If you enjoy art, then you must also see Thyssen (the best survey of Western art from the early Italians thru modern); and Reina Sofia, an incredible collection of modern art.

Here are the current OPENING TIMES of the three main museums of Madrid plus the Royal Palace. This information is current as of January 2009 but may be subject to changes in the future and become outdated:

  - MUSEO DEL PRADO.

  Opens from 9:00 to 20:00. Mondays closed.

  General fee: 6 €. Free on Sundays, from 9:00 to 19:00*.

  - MNCARS (Reina Sofía Modern Art Museum).

  Mondays, Wednesdays, Thursdays, Fridays and Saturdays, from 10:00 to 21:00

  Sundays, from 10:00 to 14:30

 Tuesdays closed

 General fee: 6 €.  Reduced fee for students: 3 €.  Free entrance for people under 18 years or older than 65, unemployed... Also free the 18th May, 12th October and 6th December*.

   - MUSEO THYSSEN-BORNEMISZA.

  Opens from 10:00 to 18:30. Closed on Mondays.

  Entrance fees: from 0 to 9 €* depending on the exhibit.

  *There is a combined entrance valid for the three museums that costs 14,5 €. It is called Abono Paseo del Arte.

  - PALACIO REAL (Royal Palace)

  Summer opening times (from April to September, inclusive):

  Mondays to Saturdays: 9:00 to 18:00

  Sundays and Public Holidays: 9:00 to 15:00

  * Some days, it closes for official ceremonies. Information number: 914548800.