You will certainly see this church if you visit Ljubljana. It's right on the fairly central Preseren Square, and a bright pink color that's visible from multiple places around the city. We enjoyed taking pictures of it as a landmark. We also took the opportunity to step inside (free to enter) for a few minutes. The interior was closed when we were first in the area (around 2:30 PM on a Saturday), with a small sign indicating hours. Since we were on the square again a couple hours later, it had reopened, so we took a look around. There are impressive frescoes on its ceiling and neat architectural details to look at and appreciate, so it was well worth the 5 minutes or so it took to enter and stroll around a little inside.

This beautiful pink churh in the middle of Preseren square was just lovely. The place was a little gem, it stood out against the typically European buildings in the square. The interior was also exquisitely beautiful to match the outside. We really enjoyed it.

"Frančiškanska Cerkev Marijinega Oznanjenja" (Franciscan Church of the Annunciation) is one of the most iconic buildings in Ljubljana: it's just in front of the Triple Bridge, and you cannot miss the pink church (the pink colour is symbolic of the Franciscan order). It was built between 1646 and 1660 on a site where two or three churches stood earlier, and it was redesigned in 1858. The frescoes in the interior were painted in the mid-19th century, and the ceiling paintings were added in the first half of the 20th century. The main altar was mostly made by the Baroque sculptor Francesco Robba (1736). Next to the church there is a Franciscan monastery dating from the 13th century. It features the richest monastic library in Slovenia, with over 70,000 books, which is the oldest library in Slovenia still working. In the monastery building, next to the library, there is a small museum. When visiting, you can buy a ticket to visit only the church, or only the museum / library, or both. I did both, and they were both very good.