The influence of Islamic Styles (such as Arabic script on buildings), Materials (such as coloured tiles) and Architecture is evident all over Spain and Portugal (as it is to a lesser extent in Puglia and Sicily). 

Mozarabs were Christians in Islamic Spain who lived as Christians - which they were permitted to do under Islamic Law provided they paid the appropriate (heavy) taxes.  Over time many fled north into the Christian held areas, and brought with them a distinctive church architecture now called Mozarabic.  With the beautiful exceptions of San Miguel de Escalada and Suso Monastery, little of this survives.

Mudéjar was the name given later on by Castilians to the surrendered Moor and Saracen communities who had been overrun as the Reconquista advanced southwards.  Although Spain had been effectively rechristianized (with the exception of Granada) by 1232, a few of these communities survived as functioning Islamic groups right down to the forced conversion of everything Spanish to Christianity in 1522.  Mudéjar architecture, which was a brickwork (and tiles) based Islamo-Christian hybrid, flourished in the 1300s and 1400s.  Examples of the style include the church of San Roman, Toledo, the cloister of Rábida Convent, the church of San Tirso in Sahagún, and the campanile of the Cistercian Abbey of Rueda.  Zaragoza and Teruel are said to have some of the finest  Mudéjar buildings (no pics yet - we didn't make it this time round!)

Spanish and Portuguese Cistercian Monasteries / Nunneries / Abbeys are marked with an *

Portugal

Alcobaça Abbey *

Batalha Monastery

Spain

Salamanca

las Duenas Convent

San Esterban Monastery

2 Cathedrals

Toledo

Toledo Cathedral

San Roman

(Mudéjar)

Santa Maria la Blanca

(ex-synagogue)

Sinagoga del Tránsito

Granada

Cathedral

Capilla Real

San Jeronimo Monastery

Cordoba

Great Mosque

Seville

Cathedral

Huelva

Rábida Convent

(& Christopher Colombus)

Santiago de Compostela

Cathedral

Leon

Cathedral

San Isidoro Basilica

Rio Esla

Gradefes Nunnery *

San Miguel de Escalada

E of Leon

Templar Church of Villalcázar de Sirga

Burgos

Cathedral

Santa Maria la real de Las Huelgas Nunnery & Royal Pantheon *   (4 pages of photos)

San Pedro de Gardina Monastery * (with the tomb of El Cid)

S of Burgos

Santo Domingo de Silos Monastery

San Millán de la Cogolla

Yuso & Suso Monasteries

Canas Nunnery * (with the famous tomb of Abbess La Beata Urraca Lopez de Haro)

Navarre

Leyre Abbey *

Santa Maria la Real, Sanguesa

La Oliva Abbey *

Aragon

Rueda Abbey  *

Catalonia

Poblet Abbey *

Santes Creus Abbey *