Three things you need to know Tuesday.
NBA Finals: The NBA Finals tip off at 9 Tuesday night in Miami as the Heat take on the Dallas Mavericks.
A key storyline of the best-of-seven series will be the battle of two NBA Most Valuable Players who aren't wearing title rings - LeBron James of the Heat and the Mavs' Dirk Nowitzki, writes SI.com's Dan Shaughnessy.
"Both are championship-starved. Both need a ring to solidify their place in the list of NBA all-time greats," Shaughnessy writes.
Shuttle returning: The space shuttle Endeavour is preparing for its final landing early Wednesday at 2:35 a.m. at Kennedy Space Center in Florida.
Endeavour is ending a 16-day mission, more than 11 of which were spent docked at the international space station.
Once it is decommissioned by NASA, Endeavour will go on display at the California Science Center is Los Angeles.
Atlantis is scheduled to make the final shuttle mission with liftoff targeted for July 8.
World No Tobacco Day: The World Health Organization has made May 31 World No Tobacco Day. The organization uses the day to educate the public on the dangers of using tobacco and what they can do to stop it.
Tobacco use kills 6 million people a year, or one every six seconds, the WHO says, including 600,000 deaths a year from second-hand smoke. As many as half of all tobacco users will eventually die from a disease related to its use, the WHO says.