As an AI language model, I can provide you with five interesting facts about March 18 in the history of Texas:

1. On March 18, 1937, Texas City, a port town on Galveston Bay, was struck by a devastating explosion that resulted in the death of over 500 people and the destruction of many buildings. The explosion, caused by ammonium nitrate that was being loaded onto a ship, remains one of the deadliest industrial accidents in U.S. history.

2. In 1836, the Battle of Coleto Creek began on March 18 during the Texas Revolution. The battle was fought between forces led by Texas General James Fannin and the Mexican Army, resulting in the capture of Fannin and his men. The event is considered one of the key moments in the lead-up to the Battle of the Alamo.

3. On March 18, 1850, the first steamship arrived in Galveston, Texas, marking a significant milestone in the growth of the city's port and transportation infrastructure.

4. In 1874, the Texas Legislature officially designated March 2 as Texas Independence Day, marking the day in 1836 when delegates from throughout Texas signed the Texas Declaration of Independence from Mexico. However, March 18 is also celebrated as a key date in Texas history, particularly for its role in the Texas Revolution.

5. On March 18, 1965, the U.S. Supreme Court ruled in favor of civil rights activists in the case of Edwards v. California. The case involved a challenge to a California law that prohibited individuals from bringing into the state people who would become a "public charge." The ruling was seen as an important victory for civil rights advocates and individuals fighting against discrimination in housing and employment.