Chalcis or Chalkida (/ˈkælsɪs/; Modern Greek: Χαλκίδα [xalˈkiða], Ancient Greek : Χαλκίς, Halkis), the chief town of the island of Euboea in Greece, is situated on the strait of Evripos at its narrowest point. The name is preserved from antiquity and is derived from the Greek χαλκός (copper, bronze), though there is no trace of any mines in the area. In the late Middle Ages, it was known as Negropont (Italian: Negroponte, "black bridge"), a name that was applied to the entire island of Euboea as well.
The earliest recorded mention of Chalcis is in Ilias (2.537), where it is mentioned in the same line as its rival Eretria. It is also documented that the ships set for the Trojan War gathered at Avlis, the south bank of the strait nearby the city. Chamber tombs at Trypa and Vromousa dated to the Mycenaean period were excavated by Papavasiliou in 1910. In the 8th and 7th centuries BC, colonists from Chalcis founded thirty townships on the peninsula of Chalcidice, and several important cities in Sicily. Its mineral produce, metal-work, purple and pottery not only found markets among these settlements, but were distributed over the Mediterranean in the ships of Corinth and Samos.
With the help of these allies, Chalcis engaged the rival league of its neighbour Eretria in the so-called Lelantine War, by which it acquired the best agricultural district of Euboea and became the chief city of the island. Early in the 6th century BC, its prosperity was broken by a disastrous war with the Athenians, who expelled the ruling aristocracy and settled a cleruchy on the site. Chalcis subsequently became a member of both the Delian Leagues. Aristotle, the great philosopher, also lived in the city.
In the Hellenistic period, it gained importance as a fortress by which the Macedonian rulers controlled central Greece. It was used by kings Antiochus III of Syria (192 BC) and Mithradates VI of Pontus (88 BC) as a base for invading Greece.
Under Roman rule, Chalcis retained a measure of commercial prosperity.
Since the 6th century the city again served as a fortress for the protection of central Greece against northern invaders. From 1205, it stood under Lombard (Veronese) control as the capital of the Triarchy of Negroponte. It came gradually under Venetian control until it became a Venetian colony in 1390. In 1470, after a long siege, it passed to the Ottomans, who made it the seat of the Admiral of the Archipelago (the Aegean Islands). In 1688, it was successfully held by the Ottomans against a strong Venetian attack.
The modern town received an impetus in its export trade from the establishment of railway connection with Athens and Piraeus in 1904. In the early 20th century it was composed of two parts—the old walled town at the bridge over the Euripus, where a number of Turkish families continued to live until the late 19th century, and a sizeable Jewish community lived until World War II, and the more modern suburb that lies outside it, chiefly occupied by Greeks. The old town, called Castro, was surrounded by a full circuit of defense walls until they were completely razed for urban development around the start of the 20th century.
The most interesting building in Chalcis is the church of Saint Paraskevi (the patron saint of the island), which was the church of the Dominican Priory of Negroponte, one of the first two houses authorized for the Province of Greece in 1249. Started about 1250, this is among the oldest examples of early Dominican architecture surviving, and is one of the only early Dominican churches to retain its original form until the present. The central arch over the iconostasis and the ceiling and walls of the south chapel are the best examples of Italian Gothic stone-carving in Greece. Images of the Dominican saints, Dominic and Peter Martyr, stand at the base of the central arch. The north chapel holds the tomb of the founder of the senatorial Lippamano family of Venice. Some of the column capitals are Byzantine.
In 1899, Chalcis became the prefectural capital of Euboea.
The town is now connected to the mainland Greece by two bridges, the "Sliding Bridge" in the west at the narrowest point of the Euripus Strait and a suspension bridge.
The Euripus Strait which separates the city and the island from the mainland was bridged in 411 BC with a wooden bridge. In the time of Justinian the fixed bridge was replaced with a movable structure. The Turks replaced this once again with a fixed bridge. In 1856, a wooden swing bridge was built; in 1896, an iron swing bridge, and in 1962, the existing "sliding bridge"; the construction works of the 19th century destroyed the most part of the medieval castle built across the bridge. The cable stay suspension bridge which joins Chalcis to the mainland to the south was opened in 1993.
A unique phenomenon takes place at the straits of Euripus. The phenomenon is known as tide. Tides are the rise and fall or water levels. The strait of Euripus is subject to strong tidal currents which reverse direction approximately four times a day lasting for about six hours each. This creates an amazing sight for visitors from all over the world.