Castel del Monte near Andria, Italy, stands on an isolated hill with eight octagonal towers at the corners of the battlements. It was built in the 1240s at the behest of Holy Roman Emperor Frederick II of Swabia.

The ruins of the 10th century Byzantine Church of Santa Maria del Buonconsiglio in Bari, Italy, feature columns, Corinthian capitals, and a mosaic floor originating in Roman times.

The Portal of the Lions of the Basilica San Nicola (1087-1197) in Bari, Italy, is richly decorated in the Byzantine and Romanesque styles.

The gilded wooden ceiling of the Basilica San Nicola in Bari, Italy, frames canvases by Baroque painter Carlo Rosa (1613-1678).

The Basilica San Nicola (1087-1197) in Bari, Italy, contains relics of Saint Nicholas brought here from Turkey in 1087.

Strada San Marco is typical of the narrow alleys in the old quarter of Bari, Italy.

In the early 16th century sloping walls and a moat were added to the medieval Castello Svevo (1139-1240) in Bari, Italy.

The Castello Svevo in Bari, Italy, was originally constructed by the Norman king Roger II around 1131. The slanting exterior walls were added in the early 16th century to counter firearms while the rectangular tower inside dates from the earlier period.

The tower of the Basilica Cattedrale Metropolitana Primaziale San Sabino rises above the waterfront in Bari, capital of the Apulia region in southeastern Italy.

The Silversea cruise ship Silver Moon tied up at Koper, Slovenia.

A remarkable display of stalagmites and stalactites are seen in the Postojna Cave in Slovenia.

A five-meter stalagmite titled Brilliant (right) and an adjacent column are symbols of the Postojna Cave, 60 km northeast of Koper, Slovenia.

Mosaics of the 5th century AD are in the flooded crypt of the Basilica di San Francesco in Ravenna, Italy. Goldfish swim in the water.

The tomb of the Italian poet Dante Alighieri (1265-1321) is in Ravenna, Italy. Dante's birthplace city Florence has tried unsuccessfully for centuries to have his remains moved there.

A late 6th century Byzantine mosaic of a procession of 26 Martyrs leaving the Palace of Theodoric is on the south wall of the Basilica di Sant'Apollinare Nuovo in Ravenna, Italy.

A Byzantine mosaic dating from 565 AD in the Basilica di Sant'Apollinare Nuovo, Ravenna, Italy, shows the Three Magi dressed as Persians moving toward four angels and the Madonna and Child.

A late 6th century Byzantine mosaic showing a procession of 22 Virgin Martyrs is in the Basilica di Sant'Apollinare Nuovo in Ravenna, Italy.