French President Emmanuel Macron, who arrived in Washington, D.C., on Monday for a state visit, gave President Donald Trump an oak tree sapling from the Belleau Wood, the site of a 1918 World War I battle where 9,000 Americans died. The gift was an appreciation for U.S. sacrifice.

Throughout history, when foreign leaders visited our presidents, they gifted them with something symbolic and often personal. But there have been times when the gifts have been a bit odd.

During a 2011 visit to Australia, President Barack Obama received crocodile insurance from the head of the Northern Territory. You know, in case the president got in a terrible accident while visiting the croc hot spot.

“I have to admit, when we reformed health care in America, crocodile insurance is one thing we left out,” Obama said with a chuckle.

President George W. Bush got a stuffed dead lion and leopard from Tanzania. In 1984, President Ronald Reagan received a baby elephant on the White House lawn dressed in traditional clothing when Sri Lanka’s president visited. While that may be over-the-top, the animal represented the friendship and similarities between the countries. The elephant is the symbol of Reagan’s political party (Republican) and was the same for the Sri Lankan ruling political party at the time.

“She is a cute little thing only 34 inches high,” Reagan noted in a 1984 diary entry.

Just like on birthdays and anniversaries, the official exchange of gifts symbolizes the friendship and journey shared between countries. It’s part of diplomacy, the managing of international relationships in a respectful and thoughtful way. Through diplomacy, the United States has been able to fix international relationships that may have started on the wrong foot.

“We fought a revolution with England, but now we refer to them as a ‘special friend.’ And we exchange wonderful gifts with them back and forth between the queen and several presidents,” says Stewart McLaurin, the president of the White House Historical Association.

But let’s face it: It must be difficult coming up with a cool present for someone who has it all. Leaders from Bermuda might have had a hard time when they gave President John Kennedy a multicolored statue of a tropical fish in 1961. He also got a drinking horn from the leader of the Soviet Union. When George W. Bush was in office, he received a vocabulary-building game from the sultan of Brunei.

“There are often gifts that are interesting,” says Kirstin Holm, a registrar of the Presidential Materials division at the National Archives. “Sometimes it’s not quite clear what the message was with the gifts given. But we treat everything as an artifact.”

Technically, all gifts given to the president from foreign nations are dedicated to the people of the United States. Each president can keep and use the presents until the next president is inaugurated. The National Archives picks up the gifts at noon, before the next president takes their new job at the White House. You can see the gifts presidents receive from foreign leaders at their presidential libraries across the country.

The Archives isn’t picking up the new tree, however. The oak was planted late Monday at the White House. Trump and future presidents won’t have to look far for a reminder of France’s friendship.