Column of Trajan, Rome, A.D. 113, Early Imperial Period

commemorates Roman emperor Trajan's victory in theDacian Wars. It was probably constructed under the supervision of the architect Apollodorus of Damascus at the order of the Roman Senate. the freestanding column is most famous for its spiral bas relief. A continuous frieze winds up around the tower from base to capital. Contains a stairway in the center of the tower. 

Pantheon, Rome, A.D. 125-128, Early Imperial Period

Made in a perfect circle and made out of solid concrete, 20 feet thick walls, 29 foot opening in the top, the symbol of master of the world, has been used as a Catholic church, The inside was transformed into a Church with gold and other metals and divided up into four sections inside.

Equestrian statue of Marcus Aureliusc. A.D. 161-80,

The longest surviving equestrian statue, Marcus was one of the best of 5 great emperors.  ancient Roman statue in the Campidoglio, Rome, Italy.  It is made of bronze and stands 3.5 m tall. The overall theme is one of power and divine grandeur. 

Tetrarchs, c. A.D. 305, porphyry

 is a sculpture group of four Roman emperors, wedged into a corner on the facade of San Marco in Venice, Italy. The tetrarchy consisted of two Augusti (senior emperors) and two Caesars (younger emperors). Each tetrarch looks the same, without any individualized characteristics. The group is divided into pairs, each embracing, which unites Augusti and Caesars together. The overall effect suggests unity and stability. 

Arch of Constantine, Rome,

2nd century and later, loculus

 is a triumphal arch in Rome, situated between the Colosseum and the Palatine Hill.

 was erected to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge.  it is the latest of the existing triumphal arches in Rome. The arch served as the finish line for the marathon athletic event for the 1960 Summer Olympics.  The arch is 21 m high, 25.9 m wide and 7.4 m deep.

Good Shepherd and Jonah, ceiling, catacomb of S.S. Pietro and Marcellino, Rome 4th Century

An early Christian burial place, the ceiling decoration in this catacomb is a great example of early Christian imagery, portraying its religious subjects in an accessible and recognizable manner.  Located just outside Rome, this catacomb contains relics of Saints Pietro and Marcellino, two third century martyrs.  Roman law protected the tombs,  The ceiling decoration here is Roman in style but Christian in subject.  A good example of syncretism, Christ’s pose is borrowed from pagan imagery of Orpheus while Jonah under the vines is similar to a sleeping Endymion.

Santa Costanza (Mausoleum of Constantina)

Rome, c. 338-50

 is a 4th century church in Rome, Italy, on the Via Nomentana, which runs north-east out of the city,  it was built under Constantine I as a mausoleum for his daughter Constantina, One key component which is missing from Santa Costanza is the art of the central dome. The structure of Santa Costanza is centralized both in its physical structure and purpose. It has a circular ringed design and domed ceiling. It was built of brick-faced concrete.

Mausoleum of Galla Placidia

Ravenna, c. 425-50

 is a Roman building in Ravenna, Italy,  is laid out in a Greek cross plan with a central dome on pendentives and barrel vaults over the four transepts, The building was formerly the oratory of the Church of the Holy Cross and now contains three sarcophagi. The interior of the mausoleum is covered with rich Byzantine mosaics, and light enters through alabaster window panels. 

San Vitale, Ravenna, c. 526-547

 styled an "ecclesiastical basilica" in the Roman Catholic Church, though it is not of architectural basilica form — is a Byzantine church in Ravenna, Italy.  the unique octagonal building style is one of the most important examples of early Christian Byzantine Art and architecture in western Europe. It served as a reminder of the Eastern-Roman Byzantine Christian presence in Italy at the time when much of the west was under Arian Ostrogothic rule. Construction of the building itself began in 527, when Ravenna was under the rule of the Ostrogoths. It was completed in 548 after Ravenna was retaken under Byzantium rule.

Hagia Sofia, Constantinople (Istanbul), c. 532-37

 is a former Orthodoxpatriarchal basilica, later a mosque, and now a museum in Istanbul, Turkey.  From the date of its dedication in 360 until 1453, it served as the Greek Patriarchal cathedral of Constantinople, except between 1204 and 1261, when it was converted to a Roman Catholic cathedral under the Latin Patriarch of Constantinople of the Western Crusader established Latin Empire. The building was a mosque from 29 May 1453 until 1931, when it was secularized. It was opened as a museum on 1 February 1935. Famous in particular for its massive dome, it is considered the epitome of Byzantine architecture^[5] and is said to have "changed the history of architecture.

Monastery of Hosios Loukas

Phocis, greece, 10th-11th century

 is an historic walled monastery situated near the town of Distomo, in Boeotia, Greece.  It is one of the most important monuments of Middle Byzantine architecture and art, and has been listed on UNESCO's World Heritage Sites. The Church of the Theotokos, the oldest in the complex, is the only church known with certainty to have been built in mainland Greece in the tenth century. The monastery derived its wealth (including funds required for construction) from the fact that the relics of St. Luke were said to have exudedmyron, a sort of perfumed oil which produced healing miracles.

St. Marks, Venice, begun 1063

 is the cathedral church of the Roman Catholic Archdiocese of Venice, northern Italy. It is the most famous of the city's churches and one of the best known examples of Byzantine architecture.  For its opulent design, gilded Byzantine mosaics, and its status as a symbol of Venetian wealth and power, from the 11th century on the building has been known by the nickname Chiesa d'Oro (Church of gold). The exterior of the basilica is divided in three registers: lower, upper, and domes. In the lower register of the façade five round-arched portals, enveloped by polychrome marble columns, open into the narthex through bronze-fashioned doors.Originally it was the chapel of the Doge, and has only been the city's cathedral since 1807.  

Cathedral of St. Basil

Kremlin, Moscow, 1554-60

 is a Russian Orthodox church erected on theRed Square in Moscow in 1555–61. Built on the order of Ivan the Terrible to commemorate the capture of Kazan and Astrakhan, it marks the geometric centre of the city and the hub of its growth since the 14th century.  It was the tallest building in Moscow until the completion of the Ivan the Great Bell Tower in 1600. The building's design, shaped as a flame of a bonfire rising into the sky, has no analogues in Russian architecture: "It is like no other Russian building. The cathedral foreshadowed the climax of Russian national architecture in the 17th century.