A wedding anniversary was the annual celebration of a marriage.
26 June 2020 marked Amy Pond and Rory Williams' tenth wedding anniversary. According to one account, the couple celebrated by travelling to Cwmtaff, Wales to wave to their younger selves, who were there with the Eleventh Doctor. (TV: The Hungry Earth) Another account suggests they'd long since left their native time period by that point, however. (TV: The Angels Take Manhatten)
Lace was the traditional gift for a thirteenth wedding anniversary. River Song stole a lace shawl, woven from extremely fine astatine lace for the occasion. When the Eleventh Doctor enquired as to whose wedding anniversary it was, she uttered her usual response: "spoilers". (COMIC: Without a Paddle)