•The exterior of Canterbury Cathedral immediately impresses by its size, but also rewards closer attention to its details. Viewed directly from the south, the abrupt change from Romanesque to Gothic is clearly evident - to the right (east) are round arches, blind arcades, and rough surfaces; to the left are the abundant pointed arches and pinnacles of the Gothic nave.

Decorating the Romanesque exterior are intertwined blind arches embellished with decoratively carved columns and figurative capitals, all of which date from Archbishop Anselm's reconstruction around 1120. Many of the capitals are weathered beyond recognition, but others still clearly display proud Green Men and other interesting medieval characters.

•The main entrance is through the Gothic southwest porch, built in 1424-25 by Thomas Mapilton and 1455-59 by Richard Beke. It was restored with new statues of Canterbury's most notable archbishops by Theodore Pfyffers in 1862. There are some details to spot here, too - look for grinning faces and tiny symbols carved along the top.

The nave terminates at a great Gothic choir screen (as known as pulpitum) at the top of a wide stairway. The pulpitum was built about 1455 by Richard Beke and originally had sculptures of Christ and the twelve apostles along with the shield-bearing angels and six kings that survive today.

East of the choir is the large Trinity Chapel, a level higher than the rest of the interior and surrounded by an ambulatory. It is reached by stone stairs on either side.

•The Trinity Chapel was built specifically for the Shrine of St. Thomas, which stood here from 1220 to 1538, when it was destroyed on orders of King Henry VIII. It has been left empty and a single candle burns over the site of the shrine.

The floor of the Trinity Chapel, near the west end, has a set of interesting inlaid marble roundels representing the signs of the zodiac, months of the year, virtues and vices. These were added to embellish the shrine. 

The ambulatory around the Trinity Chapel is home to some of the most interesting and accomplished stained glass in Canterbury Cathedral. Most of the glass is original, ranging in date from about 1180 to 1220, but there were significant restorations and replacements made in the 19th century.

Circling around the ambulatory are a total of eight windows depicting the Miracles of St. Thomas Becket. The first window, in the north ambulatory, depicts some of the events leading to his martyrdom, but the rest tell stories of ordinary people who experienced miracles by praying to the saint or visiting his shrine.

The narratives depicted in these windows provide a fascinating glimpse into medieval life, particularly its most common illnesses and accidents. Many scenes take place around Thomas' tomb, which is shown in its original position in the crypt. It was only after the Trinity Chapel and its windows were completed that his relics were moved to the new shrine.

The far east end of the cathedral is occupied by an apse chapel known as the Corona ("crown"), because it once housed the relic of St. Thomas' head. Here there are two more medieval windows of interest: the Tree of Jesse and the Redemption Window. Both date from about 1200.

From the Tree of Jesse only two original panels survive, which are displayed in the far left window: King Josiah and the Virgin Mary. The entire window has been reconstructed with modern glass to its right. The Redemption Window is a typological window, showing four Old Testament "types" (foreshadowing events) for each of five scenes related to the Passion and Resurrection of Christ. 

Two more typological windows, equally fascinating, survive in the north choir aisle. They are earlier than the Becket Windows, dated to about 1180. There were originally six of these windows.

For a good look at most of the medieval stained glass found throughout the cathedral.

Another notable feature of the ambulatory are its many tombs of archbishops and royals. The most famous of these is the Tomb of the Black Prince (1330-76), topped with a bronze chainmailed effigy of the knight, in the south ambulatory. It's not clear how he got his romantic nickname; his contemporaries knew him as Edward of Woodstock, Prince of Wales. He was the eldest son of a king (Edward III) and the father of a king (Richard II), but was never king himself because he died before his father.

•The massive crypt beneath the east end of the cathedral is one of the most fascinating parts of the building. Built under Archbishop Anselm in the early 1100s, it still has extensive Romanesque murals and exquisitely carved columns and capitals.