Kiribati moved the International Date Line in 1995 so its eastern islands could share a calendar date with the rest of the country.
Kiribati is an island nation spread across a huge area of the central Pacific. Before the change, the Phoenix and Line Islands lay on different sides of the date line from the Gilbert Islands, creating a gap of several calendar days within one country. The government altered the time-zone arrangement so the country could observe the same date across its island groups.
The change made the Line Islands among the first inhabited places to enter a new calendar day. Kiritimati, also known as Christmas Island, became particularly famous for welcoming the new year early. This is why travel and news stories often describe Kiribati as one of the first countries to celebrate New Year's Day.
The International Date Line is not a perfectly straight legal boundary. It bends around national territories and practical time-zone choices. Kiribati's adjustment changed the official local dates without physically moving a line across the Pacific.