Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 23 to 30

The Forbidden City is the former imperial palace in the center of Beijing, China. Construction began in 1406, and the emperor's court officially moved in by 1420. The Forbidden City got its name because most people were barred from entering the 72-hectare site, surrounded by walls. Even government officials and the imperial family were permitted only limited access. Only the emperor could enter any section at will.

The architecture of the Forbidden City conforms rigidly to traditional Chinese principles. All buildings within the walls follow a north-south line and the most important ones face south to honor the sun. The designers arranged the other buildings, and the ceremonial spaces between them, to impress all visitors with the great power of the Emperor, while reinforcing the insignificance of the individual. This architectural concept was carried out to the smallest detail. For example, the importance of a building was determined not only by its height or width but also by the style of its roof and the quantity of statuettes placed on the roof’s ridges.

In recognition of the importance of its unparalleled architecture, UNESCO added the palace to its World Heritage List in 1987. Today, visitors from all over the world do not wait for an imperial invitation to walk about this palace, now a museum of imperial art.

One of the most impressive landmarks of the Forbidden City is the Meridian Gate, the formal entrance to the southern side of the Forbidden City. The gate, with its auxiliary wings on either side of the entryway, is 38 meters high at its roof ridge. When you stand in front of this majestic structure, you understand how awed people felt when they stood there listening to imperial proclamations.

As you walk through the gate, you come into a large courtyard, 140 meters long and 210 meters wide. Running through the courtyard is the Golden River, which is crossed by five parallel white marble bridges. These bridges lead to the Gate of Supreme Harmony, which, in turn, leads to the heart of the Forbidden City. At the northernmost end of the Forbidden City is the Imperial Garden, which is totally different from the rest of the compound. Instead of rigid formality, you see a seemingly spontaneous arrangement of trees, fishponds, flowerbeds, and sculpture. Here is the place of relaxation for the emperor.
Question:Which phrase is closest in meaning to the word 'unparalleled' as used in paragraph 3?

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