The Seventh-day Adventist Church is a group of people who believe in Jesus and follow the Bible. They are called "Seventh-day" because they believe that the seventh day of the week, which is Saturday, is holy and should be kept as a day of rest and worship. This makes them different from most other Christians who worship on Sundays.
The Adventist Church was started in the 1800s by a man named William Miller who believed that Jesus would come again soon. When Jesus did not come as expected, a group of people in the movement discovered new teachings about keeping the seventh day holy and following other religious practices like vegetarianism, avoiding alcohol and tobacco, and wearing modest clothing.
Today, the Seventh-day Adventist Church is a worldwide community of about 21 million people who follow these teachings and believe in living healthy, happy lives that honor God. They have their own schools, hospitals, and other institutions that reflect their beliefs and values. Adventists are known for being friendly and helpful, and are active in their local communities around the world.